Method for inspecting multi-connected air conditioning system and multi-connected air conditioning system

Abstract

The application provides a commercial inspection method of a multi-connected air conditioning system and the multi-connected air conditioning system. The commercial inspection method comprises the following steps: step S1: controlling two four-way valves to be powered on, a first electromagnetic valve to be closed, and all throttles to be opened; step S2: judging whether high pressure is greater than a first predetermined value; step S31: if the high pressure is greater than the first predetermined value, controlling the first four-way valve to be powered on, the second four-way valve to be powered off, and the second throttle to be closed; detecting an indoor unit refrigeration heating state and detecting whether low pressure is lower than a second predetermined value; step S311: judging whether the four-way valve is reversed, whether the throttle is reversed, according to the detection result of step S31; and judging whether the first throttle and the second throttle are faulty in turn under the conditions that the four-way valve is reversed and unreversed; step S32: if the high pressure is not greater than the first predetermined value, detecting the indoor unit refrigeration heating state and detecting whether the low pressure is lower than the second predetermined value to judge whether the four-way valve is faulty, whether the first throttle is faulty, whether the throttle is reversed, and whether the second throttle is faulty.

Description

Technical Field

[0001] This invention relates to the field of air conditioning, specifically to a commercial inspection method for a multi-split air conditioning system and a multi-split air conditioning system. Background Technology

[0002] Existing multi-split air conditioning systems with dual four-way valves and dual throttling valves are prone to incorrect connection during factory assembly due to the large number of four-way valves and throttling valves and the complex piping. There are also instances where faulty four-way valves or throttling valves go undetected. To ensure the reliability of multi-split air conditioning systems entering the market, current technology typically relies on worker responsibility and labeling to inspect four-way valves and throttling valves. Labeling is prone to errors, and worker skill levels can affect assembly accuracy. If reversed or faulty products enter the market, it can cause system malfunctions, hinder the implementation of designed functions, and negatively impact user experience. Summary of the Invention

[0003] To address the above problems, this invention provides a commercial inspection method and system for multi-split air conditioning systems. By opening the first four-way valve, the second four-way valve, the first throttle valve, the second throttle valve, and the indoor unit throttle valve, while closing the first solenoid valve, the method detects whether the high pressure exceeds a first predetermined value. Based on the high pressure detection result, the commercial inspection logic is divided into control logic for high pressure exceeding the first predetermined value and control logic for high pressure not exceeding the first predetermined value (including different operating conditions such as cooling and heating), and different judgment logics are executed accordingly. This achieves automated detection of the four-way valves and throttle valves, saving labor, improving detection efficiency, ensuring the accuracy of commercial inspection of the multi-split air conditioning system, and improving product quality stability.

[0004] This invention provides a commercial inspection method for a multi-split air conditioning system. The multi-split air conditioning system includes: a compressor, a first four-way valve, a second four-way valve, an outdoor unit, an indoor unit, a first throttle valve, a second throttle valve, an indoor unit throttle valve, a first branch pipe, and a first solenoid valve. The compressor outlet is connected to the D1 port of the first four-way valve and the D2 port of the second four-way valve, respectively. The compressor inlet is connected to the S1 port of the first four-way valve and the S2 port of the second four-way valve, respectively. The C1 port of the first four-way valve is connected to the indoor unit, and the C2 port of the second four-way valve is connected to the outdoor unit. The E1 port of the four-way valve is connected to the S1 port; the E2 port of the second four-way valve is connected to the S2 port; the outdoor unit is connected to the indoor unit, and a first throttle valve and an indoor unit throttle valve are connected sequentially between the outdoor unit and the indoor unit; the first end of the first branch pipe is connected to the compressor, and the second end of the first branch pipe is connected between the first throttle valve and the indoor unit throttle valve; a first solenoid valve and a second throttle valve are sequentially provided from the first end of the first branch pipe to the second end of the first branch pipe; a temperature detection module is used to detect the temperature T of the refrigerant between the second throttle valve and the first solenoid valve; the commercial inspection method includes the following steps. Step S1: Power on the first four-way valve and the second four-way valve, close the first solenoid valve, and open the first throttle valve, the second throttle valve, and the indoor unit throttle valve; Step S2: Determine if the high pressure is greater than the first predetermined value; Step S31: If the high pressure is greater than the first predetermined value, power on the first four-way valve, de-power the second four-way valve, close the second throttle valve, keep the first throttle valve open, and keep the first solenoid valve closed; Detect the indoor unit's cooling / heating status and detect if the low pressure is lower than the second predetermined value; Step S311: Based on the indoor unit's cooling / heating status and whether the low pressure is lower than the second predetermined value, determine... Check if the first four-way valve and the second four-way valve are connected in reverse, and determine if the first throttle valve and the second throttle valve are connected in reverse; and in the cases where the first four-way valve and the second four-way valve are connected in reverse and not in reverse, respectively determine if the first throttle valve is faulty and determine if the second throttle valve is faulty; Step S32: If the high pressure is not greater than the first predetermined value, check the cooling and heating status of the indoor unit and check if the low pressure is lower than the second predetermined value to determine if the first four-way valve or the second four-way valve is faulty, and determine if the first throttle valve is faulty; determine if the first throttle valve and the second throttle valve are connected in reverse and determine if the second throttle valve is faulty.

[0005] According to this technical solution, when the first four-way valve and the second four-way valve are energized, if the high pressure exceeds the first predetermined value, it indicates that the refrigerant at the compressor outlet is blocked, and the D1 interface is connected to the E1 interface, and the D2 interface is connected to the E2 interface. Further, by detecting the cooling / heating status of the indoor unit, it is determined whether the first and second four-way valves are connected in reverse. In both reversed and non-reverse configurations, the first throttle valve and the second throttle valve are sequentially checked for malfunction, thus achieving detection of the installation conditions of the four-way valves and throttle valves under the first operating condition. When the high pressure is not greater than the first predetermined value and the indoor unit is detected to be cooling, it indicates that the second four-way valve is de-energized. Under the condition that the second four-way valve is de-energized, the malfunction of the first throttle valve, the reverse insertion of the first and second throttle valves, and the second... The detection logic, including checking for throttle valve malfunction, enables the testing of the four-way valve and throttle valve installation under the second operating condition. When the high pressure is not greater than a predetermined value and the indoor unit is detected to be heating, it indicates that the first four-way valve is de-energized. Under this de-energized condition, the system further checks for malfunctions in the first throttle valve, whether the first and second throttle valves are reversed, and the second throttle valve itself, thus enabling the testing of the four-way valve and throttle valve installation under the third operating condition. This comprehensive testing logic ensures the detection of the four-way valve and throttle valve under various installation conditions, guaranteeing the factory quality of the multi-split air conditioning system. Furthermore, by first determining the malfunction of the four-way valve, then checking for malfunctions in the first throttle valve, reversed insertion of the first and second throttle valves, and finally the malfunction of the second throttle valve, the accuracy of the four-way valve and throttle valve testing is improved.

[0006] In the optional technical solution of the present invention, in step S311, "determining whether the first four-way valve and the second four-way valve are connected in reverse, and determining whether the first throttle valve and the second throttle valve are connected in reverse, based on the indoor unit's cooling / heating status and whether the low pressure is lower than the second predetermined value; and sequentially determining whether the first throttle valve is faulty and whether the second throttle valve is faulty under the conditions of the first four-way valve and the second four-way valve being connected in reverse and not connected in reverse" includes: Step S3111: If the indoor unit is cooling and the low pressure is lower than the second predetermined value, the first throttle valve and the second throttle valve are connected in reverse; if the low pressure is not lower than the second predetermined value, sequentially determining whether the first throttle valve is faulty. The steps include: determining whether the first throttle valve is faulty and outputting that the first four-way valve and the second four-way valve are not connected in reverse; step S3111 or step S311's "sequentially determining whether the first throttle valve is faulty and determining whether the second throttle valve is faulty" includes: controlling the first four-way valve to de-energize, the second four-way valve to energize, the first throttle valve to close, the second throttle valve to close, the indoor unit throttle valve to open, and the first solenoid valve to open; and detecting whether the low pressure is lower than the second predetermined value; if the low pressure is lower than the second predetermined value, outputting that the first throttle valve is not faulty and determining whether the second throttle valve is faulty; if the low pressure is not lower than the second predetermined value, outputting that the first throttle valve is faulty.

[0007] According to the technical solution, in step S31, the first four-way valve is energized and the second four-way valve is de-energized, the second throttle valve is closed, the first throttle valve and the indoor unit throttle valve remain open, and the first solenoid valve remains closed. The air conditioner should be cooling. The refrigerant at the compressor outlet passes through the second four-way valve, the outdoor unit, the first throttle valve, the indoor unit throttle valve, and the indoor unit back to the compressor in sequence. If the indoor unit is detected to be cooling in step S3111, it indicates that the first four-way valve and the second four-way valve are not reversed. However, it is not ruled out that the first four-way valve and the second four-way valve are stuck in the energized state. If the low pressure is lower than the second predetermined value, it indicates that the refrigerant is cut off at the first throttle valve, and the first throttle valve is in the closed state, which is opposite to the open state that the first throttle valve should respond to. The first throttle valve and the second throttle valve are reversed.

[0008] If the low pressure is not lower than the second predetermined value, it indicates that refrigerant is returning to the compressor. Further control is implemented by de-energizing the first four-way valve, energizing the second four-way valve, closing the first throttle valve, closing the second throttle valve, opening the indoor unit throttle valve, and opening the first solenoid valve. The air conditioner then heats up, and the refrigerant flows sequentially through the first four-way valve, the indoor unit, and finally to the indoor unit throttle valve. If the low pressure is lower than the second predetermined value at this point, it indicates that the first throttle valve is functioning correctly. If the low pressure is not lower than the second predetermined value, it indicates that the first throttle valve is not completely closed, and refrigerant is returning to the compressor through the first throttle valve, indicating a fault in the first throttle valve. Furthermore, compared to the four-way valve's open / closed state in step S31, the change in the four-way valve's state causes a change in the refrigerant flow direction, indicating that the first and second four-way valves are not only not reversed but also not jammed, thus improving the accuracy of the four-way valve's judgment.

[0009] In the optional technical solution of the present invention, in step S311, "determining whether the first four-way valve and the second four-way valve are connected in reverse according to the cooling and heating status of the indoor unit and whether the low pressure is lower than the second predetermined value, determining whether the first throttle valve and the second throttle valve are connected in reverse, and determining whether the first throttle valve is faulty and whether the second throttle valve is faulty in the reversed and unreversed conditions respectively" includes: step S3112: if the indoor unit is heating and the low pressure is lower than the second predetermined value, output that the first throttle valve and the second throttle valve are connected in reverse; if the low pressure is not lower than the second predetermined value, determine whether the first throttle valve is faulty and whether the second throttle valve is faulty in sequence, and output that the first four-way valve and the second four-way valve are connected in reverse. In step S3112 or step S312, "sequentially determining whether the first throttle valve is faulty and determining whether the second throttle valve is faulty" includes: controlling the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be closed, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened; detecting whether the low pressure is lower than the second predetermined value; if the low pressure is not lower than the second predetermined value, then outputting that the first throttle valve is faulty; if the low pressure is lower than the second predetermined value, then outputting that the first throttle valve is not faulty, and determining whether the second throttle valve is faulty.

[0010] According to this technical solution, if the indoor unit is detected to be heating, the refrigerant from the compressor outlet returns to the compressor via the first throttle valve, the indoor unit, the indoor unit throttle valve, the first throttle valve again, and the second four-way valve. This indicates that the first four-way valve is de-energized, which is the opposite of the state of the first four-way valve in step S31, meaning that the first and second four-way valves are connected in reverse. Furthermore, if the low pressure is detected to be lower than a second predetermined value, the refrigerant is cut off at the first throttle valve, which is closed, the opposite of the open state in step S31, meaning the first and second throttle valves are connected in reverse. If the low pressure is not lower than the second predetermined value, keep the first four-way valve energized and the second four-way valve de-energized. Close the first and second throttle valves, and open the indoor unit throttle valve and the first solenoid valve. The four-way valves remain in the heating state. The refrigerant from the compressor outlet passes through the first four-way valve, the indoor unit, and the indoor unit throttle valve before being cut off by the first throttle valve. If the low pressure is lower than the second predetermined value, it indicates that the first throttle valve is not faulty, and further investigation is needed to determine if the second throttle valve is faulty. If the low pressure is not lower than the second predetermined value, it indicates that the first throttle valve is open, contrary to the theoretical open state, indicating that the first throttle valve is faulty, while the first four-way valve is not faulty.

[0011] In the optional technical solution of the present invention, "determining whether the second throttle valve is faulty" includes: controlling the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be opened, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened; detecting whether the temperature change of temperature T is within the specified range; if it is within the specified range, outputting that the second throttle valve is fault-free; if the temperature change exceeds the specified range, outputting that the second throttle valve is faulty.

[0012] According to this technical solution, when the four-way valve, throttle valve, and on / off valve are in the above-mentioned states, the air conditioning system cools, and the main refrigerant flows sequentially through the compressor, the second four-way valve, the outdoor unit, the first throttle valve, the indoor unit throttle valve, and back to the compressor. When the second throttle valve is closed, if no refrigerant enters the compressor from the second throttle valve through the first solenoid valve, the change in temperature T is within the specified range, indicating that the second throttle valve is not faulty. If refrigerant enters the compressor from the second throttle valve through the first solenoid valve, the change in temperature T is large, exceeding the specified range, indicating that the second throttle valve is faulty.

[0013] In the optional technical solution of the present invention, in step S32, if the indoor unit is refrigerated and the low pressure is lower than the second predetermined value, the first throttle valve fault and the second four-way valve fault are output; if the indoor unit is refrigerated and the low pressure is not lower than the second predetermined value, the step of determining whether the first throttle valve and the second throttle valve are connected in reverse is executed.

[0014] According to this technical solution, if the indoor unit is refrigerating, it indicates that the second four-way valve is in a de-energized state, contrary to the energized state that the second four-way valve should reach in step S1. The second four-way valve does not respond to the energizing command, indicating that the second four-way valve is faulty. If the low pressure is lower than the second predetermined value, it indicates that no refrigerant returns to the compressor, and the refrigerant at the outdoor unit outlet is cut off at the first throttle valve, indicating that the first throttle valve is faulty. If the low pressure is not lower than the second predetermined value, it indicates that the first throttle valve is in the open state (including being stuck in the open state or opening in response to a normal opening command). Further judgment is made on whether the first and second throttle valves are connected in reverse. Based on the judgment results of the first and second throttle valves, it is determined whether the first throttle valve is fault-free, thus improving the accuracy of the first throttle valve fault judgment.

[0015] In the optional technical solution of the present invention, the step of determining whether the first throttle valve and the second throttle valve are connected in reverse includes: controlling the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be opened, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be closed; detecting whether the low pressure is lower than a second predetermined value; if the low pressure is lower than the second predetermined value, then outputting that the first throttle valve and the second throttle valve are connected in reverse, and that the first throttle valve is not faulty; if the low pressure is not lower than the second predetermined value, determining whether the first throttle valve is faulty and whether the second throttle valve is faulty.

[0016] According to this technical solution, the first four-way valve is energized, the second four-way valve is de-energized, the first throttle valve opens, the second throttle valve closes, the indoor unit throttle valve opens, and the first solenoid valve opens. The refrigerant from the compressor outlet sequentially passes through the second four-way valve, the outdoor unit, the first throttle valve, the indoor unit throttle valve, and back to the compressor. If the low pressure is lower than a second predetermined value, it indicates that the refrigerant is cut off at the first throttle valve, which is in a closed state, contrary to its expected open state. The first and second throttle valves are reversed (whether the second throttle valve is faulty is unknown and will be determined in subsequent processes); the first throttle valve is not faulty. If the low pressure is not lower than the second predetermined value, further determination is made regarding whether the first and second throttle valves are faulty, improving the completeness and accuracy of the throttle valve determination.

[0017] In the optional technical solution of the present invention, in step S32, if the internal unit heats up and the low pressure is lower than the second predetermined value, the first throttle valve fault and the first four-way valve fault are output; if the internal unit heats up and the low pressure is not lower than the second predetermined value, it is determined whether the first throttle valve and the second throttle valve are connected in reverse, whether the first throttle valve is faulty, and whether the second throttle valve is faulty.

[0018] According to this technical solution, if the indoor unit is heating, it indicates that the first four-way valve is in a de-energized state, contrary to the energized state that the first four-way valve should reach in step S1. The first four-way valve does not respond to the energizing command, indicating that the first four-way valve is faulty. If the low pressure is lower than the second predetermined value, it indicates that no refrigerant returns to the compressor, and the refrigerant at the indoor unit outlet is cut off at the first throttle valve, indicating that the first throttle valve is faulty. If the low pressure is not lower than the second predetermined value, it indicates that the first throttle valve is in an open state (including being stuck in an open state or opening in response to a normal opening command). Further determination is made as to whether the first and second throttle valves are connected in reverse. If they are not connected in reverse, further determination is made as to whether the first and second throttle valves are faulty, thus improving the accuracy of throttle valve fault diagnosis.

[0019] In the optional technical solution of the present invention, determining whether the first throttle valve and the second throttle valve are connected in reverse, whether the first throttle valve is faulty, and whether the second throttle valve is faulty includes: controlling the first four-way valve to be de-energized, the second four-way valve to be energized, the first throttle valve to be opened, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be closed; detecting whether the indoor unit is heating, and when the indoor unit is heating, detecting whether the low pressure is lower than a second preset value; if the low pressure is lower than the second preset value, then outputting that the first throttle valve and the second throttle valve are connected in reverse; if the low pressure is not lower than the second preset value, then controlling the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be closed, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened; detecting again whether the low pressure is lower than the second preset value; if the low pressure is lower than the second preset value, then outputting that the first throttle valve is fault-free; if the low pressure is not lower than the second preset value, then outputting that the first throttle valve is fault-free, and determining whether the second throttle valve is faulty.

[0020] According to this technical solution, the system controls the first four-way valve to be de-energized, the second four-way valve to be energized, the first throttle valve to open, the second throttle valve to close, the indoor unit throttle valve to open, and the first solenoid valve to close. It also detects whether the indoor unit is heating, which verifies again that a malfunction in the first four-way valve causes the indoor unit to heat, improving the accuracy of the diagnosis. By controlling the opening and closing states of the first and second throttle valves to be reversed, and based on the refrigerant flow direction and low-pressure detection results under these reversed opening and closing states, it is possible to determine whether the first and second throttle valves are connected in reverse. Specifically, under normal circumstances, the refrigerant at the compressor outlet sequentially passes through the first four-way valve, the indoor unit, the indoor unit throttle valve, the first throttle valve, the outdoor unit, and the second four-way valve back to the compressor. If the low pressure is lower than a predetermined value, it indicates that the refrigerant has not returned to the compressor, and the refrigerant at the indoor unit throttle valve outlet is cut off at the first throttle valve, i.e., the first throttle valve is closed, which is opposite to the expected opening state of the first throttle valve, indicating that the first and second throttle valves are connected in reverse. Furthermore, if the low pressure is not lower than the second predetermined value, the air conditioning system cools by controlling the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be closed, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened. The refrigerant at the compressor outlet passes through the second four-way valve and is cut off at the first throttle valve of the outdoor unit. If the low pressure is lower than the second predetermined value, it indicates that the first throttle valve is closed and there is no fault in the first throttle valve. If the low pressure is not lower than the second predetermined value, it indicates that there may be refrigerant returning to the compressor from the indoor unit throttle valve or the indoor unit, or that the second throttle valve is faulty and not closed, and the refrigerant returns to the compressor through the second throttle valve and the first solenoid valve. Therefore, by continuing to judge whether the second throttle valve is faulty, the fault condition of the second throttle valve is determined, and the fault detection of the first throttle valve, the second throttle valve and the first four-way valve is realized, ensuring the operational reliability of the air conditioning system.

[0021] In the optional technical solution of the present invention, "determining whether the second throttle valve is faulty" includes: controlling the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be opened, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened; detecting whether the temperature change of temperature T is within the specified range; if it is within the specified range, outputting that the second throttle valve is fault-free; if the temperature change exceeds the specified range, outputting that the second throttle valve is faulty.

[0022] According to this technical solution, when the four-way valve, throttle valve, and on / off valve are in the above-mentioned states, the air conditioning system cools, and the main refrigerant flows sequentially through the compressor, the second four-way valve, the outdoor unit, the first throttle valve, the indoor unit throttle valve, and back to the compressor. When the second throttle valve is closed, if no refrigerant enters the compressor from the second throttle valve through the first solenoid valve, the change in temperature T is within the specified range, indicating that the second throttle valve is not faulty. If refrigerant enters the compressor from the second throttle valve through the first solenoid valve, the change in temperature T is large, exceeding the specified range, indicating that the second throttle valve is faulty.

[0023] The present invention also provides a multi-split air conditioning system, which performs the above-described commercial inspection method for the multi-split air conditioning system. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a multi-split air conditioning system according to an embodiment of the present invention.

[0025] Figure 2 This is a flowchart illustrating steps S1 to S312 in the commercial inspection method for a multi-split air conditioning system according to an embodiment of the present invention.

[0026] Figure 3 This is a flowchart illustrating step S3111 of the commercial inspection method for a multi-split air conditioning system in an embodiment of the present invention.

[0027] Figure 4 This is a flowchart illustrating step S3112 in the commercial inspection method for a multi-split air conditioning system according to an embodiment of the present invention.

[0028] Figure 5 This is a flowchart illustrating step S321 of the commercial inspection method for a multi-split air conditioning system in an embodiment of the present invention.

[0029] Figure 6 This is a flowchart illustrating step S322 of the commercial inspection method for a multi-split air conditioning system in an embodiment of the present invention.

[0030] Figure 7 This is a flowchart illustrating step S33 of the commercial inspection method for a multi-split air conditioning system in an embodiment of the present invention.

[0031] Figure label:

[0032] Compressor 11; Outdoor unit 12; Gas-liquid separator 13; Indoor unit 2; First branch pipe 31; Second branch pipe 32; Temperature detection module 4; First four-way valve ST1; Second four-way valve ST2; First throttle valve EXV1; Second throttle valve EXV2; Indoor unit throttle valve EXV; First solenoid valve SV1; Second solenoid valve SV2. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Please see Figure 1As shown, this invention provides a multi-split air conditioning system, including: a compressor 11, a first four-way valve ST1, a second four-way valve ST2, an outdoor unit 12 (referring to the outdoor heat exchanger), an indoor unit 2 (referring to the indoor heat exchanger), a first throttle valve EXV1, a second throttle valve EXV2, an indoor unit throttle valve EXV1, a first branch pipe 31, a first solenoid valve SV1, a second branch pipe 32, a second solenoid valve SV2, and a temperature detection module 4; wherein, the outlet of the compressor 11 is connected to the d1 interface of the first four-way valve ST1 and the d2 interface of the second four-way valve ST2, and the inlet of the compressor 11 is connected to the s1 interface of the first four-way valve ST1 and the s2 interface of the second four-way valve ST2. The c1 interface of the first four-way valve ST1 is connected to the indoor unit 2, and the c2 interface of the second four-way valve ST2 is connected to the outdoor unit 12; the e1 interface of the first four-way valve ST1 is connected to the s1 interface, and the e2 interface of the second four-way valve ST2 is connected to the s2 interface. The outdoor unit 12 is connected to the indoor unit 2, and a first throttle valve EXV1 and an indoor throttle valve EXV are sequentially connected between the outdoor unit 12 and the indoor unit 2. The first end of the first branch pipe 31 is connected to the compressor 11, and the second end of the first branch pipe 31 is connected between the first throttle valve EXV1 and the indoor throttle valve EXV. A first solenoid valve SV1 and a second throttle valve EXV2 are sequentially provided from the first end to the second end of the first branch pipe 31. The first end of the second branch pipe 32 is connected to the first throttle valve EXV1, and the second end of the second branch pipe 32 is connected to the inlet of the compressor 11. The second solenoid valve SV2 is located on the second branch pipe 32. The temperature detection module 4 is used to detect the temperature of the refrigerant between the second throttle valve EXV2 and the first solenoid valve SV1. The commercial inspection method includes the following steps:

[0035] Step S1: As Figure 2 As shown, the first four-way valve ST1 and the second four-way valve ST2 are energized, the first solenoid valve SV1 is closed, and the first throttle valve EXV1, the second throttle valve EXV2, and the indoor unit throttle valve EXV are opened.

[0036] Step S2: Determine whether the high voltage is greater than the first predetermined value;

[0037] Step S31: If the high pressure is greater than the first predetermined value, control the first four-way valve ST1 to be energized and the second four-way valve ST2 to be de-energized, close the second throttle valve EXV2, keep the first throttle valve EXV1 open and the first solenoid valve SV1 closed; detect the cooling and heating status of the indoor unit 2 and detect whether the low pressure is lower than the second predetermined value.

[0038] Step S311: As Figure 2 , Figure 3 , Figure 4As shown, based on the cooling / heating status of the indoor unit 2 and whether the low pressure is lower than the second predetermined value, it is determined whether the first four-way valve ST1 and the second four-way valve ST2 are connected in reverse, and whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse; and under the conditions of the first four-way valve ST1 and the second four-way valve ST2 being connected in reverse and not connected in reverse, it is determined whether the first throttle valve EXV1 is faulty and whether the second throttle valve EXV2 is faulty.

[0039] Step S32: As Figure 5 , Figure 6 As shown, if the high pressure is not greater than the first predetermined value, the cooling and heating status of the indoor unit 2 is detected and the low pressure is detected as lower than the second predetermined value. It is determined whether the first four-way valve ST1 or the second four-way valve ST2 is faulty, and whether the first throttle valve EXV1 is faulty; it is determined whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse and whether the second throttle valve EXV2 is faulty.

[0040] Step S33: As Figure 7 As shown, if the low pressure is lower than the second predetermined value and there is no abnormal airflow from the indoor unit 2, it indicates that the first four-way valve ST1 and the second four-way valve ST2 are stuck at the DC end; control the first throttle valve EXV1 to open, the second throttle valve EXV2 to open, the indoor unit throttle valve EXV to close, and the first solenoid valve SV1 to open; and check whether the low pressure is lower than the second predetermined value; if the low pressure is lower than the second predetermined value, output that the second throttle valve EXV2 is faulty, the first four-way valve ST1 and the second four-way valve ST2 are faulty; if the low pressure is not lower than the second predetermined value, determine whether the second throttle valve EXV2 is faulty, and based on the result of determining whether the second throttle valve EXV2 is faulty, sequentially determine whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse, and whether the first throttle valve EXV1 is faulty.

[0041] In this embodiment, when the first four-way valve ST1 and the second four-way valve ST2 are energized, if the high pressure is greater than the first predetermined value, it indicates that the refrigerant at the outlet of compressor 11 is blocked, and the d1 interface is connected to the e1 interface, and the d2 interface is connected to the e2 interface. If the high pressure is not greater than the first predetermined value and the indoor unit is detected to be cooling, it indicates that the second four-way valve ST2 is de-energized; if the high pressure is not greater than the second predetermined value and the indoor unit is detected to be heating, it indicates that the first four-way valve ST1 is de-energized; if the high pressure is not greater than the second predetermined value and the indoor unit is neither cooling nor heating, it indicates that the d1 interface and the c1 interface are connected, the d2 interface and the c2 interface are connected, and both the first four-way valve ST1 and the second four-way valve ST2 are stuck at the dc end, thus realizing the detection of the four-way valves; furthermore, by adjusting the opening and closing states of the first four-way valve ST1, the second four-way valve ST2, the first throttle valve EXV1, and the second throttle valve EXV1, the detection of the four-way valves is achieved. By analyzing the refrigerant's theoretical flow direction and combining it with low-pressure detection, the actual flow direction can be determined. Based on the comparison between the actual and theoretical flow directions, the actual response state of the four-way valve and the throttle valve can be deduced. This allows for the determination of whether the first four-way valve ST1 and the second four-way valve ST2 are inserted in reverse, whether the first throttle valve EXV1 and the second throttle valve EXV2 are inserted in reverse, and whether the first throttle valve EXV1 and the second throttle valve EXV2 are faulty. This achieves automated factory testing of the four-way valves and expansion valves in multi-split air conditioning systems with dual four-way valves and dual expansion valves, ensuring the factory quality of multi-split air conditioning systems.

[0042] The following, in conjunction with the accompanying drawings, details the specific judgment process for detecting the first four-way valve ST1, the second four-way valve ST2, the first throttle valve EXV1, and the second throttle valve EXV2 in this embodiment. This embodiment can quickly determine whether the four-way valves and throttle valves are inserted backwards or are malfunctioning without increasing equipment modification costs, and can detect errors in worker assembly, thus improving detection efficiency and accuracy.

[0043] <High voltage is greater than the first predetermined value>

[0044] In a preferred embodiment of the present invention, step S311, "determining whether the first four-way valve ST1 and the second four-way valve ST2 are connected in reverse according to the cooling and heating status of the indoor unit 2 and whether the low pressure is lower than the second predetermined value, and determining whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse; and determining whether the first throttle valve EXV1 is faulty and whether the second throttle valve EXV2 is faulty under the conditions of the first four-way valve ST1 and the second four-way valve ST2 being connected in reverse and not connected in reverse respectively", includes steps S3111 and S3112.

[0045] Specifically, such as Figure 3As shown, in step S3111: if the indoor unit 2 is cooling and the low pressure is lower than the second predetermined value, output that the first throttle valve EXV1 and the second throttle valve EXV2 are reversed; if the low pressure is not lower than the second predetermined value, sequentially determine whether the first throttle valve EXV1 is faulty, determine whether the second throttle valve EXV2 is faulty, and output that the first four-way valve ST1 and the second four-way valve ST2 are not reversed; the step S3111 "sequentially determine whether the first throttle valve EXV1 is faulty, determine whether the second throttle valve EXV2 is faulty" includes: controlling the first four-way valve ST1 to be de-energized, the second four-way valve ST2 to be energized, the first throttle valve EXV1 to be closed, the second throttle valve EXV2 to be closed, the indoor unit throttle valve EXV1 to be opened, and the first solenoid valve SV1 to be opened; and detecting whether the low pressure is lower than the second predetermined value; if the low pressure is lower than the second predetermined value, then determine whether the second throttle valve EXV2 is faulty; if the low pressure is not lower than the second predetermined value, then output that the first throttle valve EXV1 is faulty.

[0046] In this embodiment, in step S31, the first four-way valve ST1 is energized and the second four-way valve ST2 is de-energized, the second throttle valve EXV2 is closed, the first throttle valve EXV1 and the indoor unit throttle valve EXV remain open, and the first solenoid valve SV1 remains closed. The air conditioner should be cooling. The refrigerant from the compressor 11 outlet passes through the second four-way valve ST2, the outdoor unit 12, the first throttle valve EXV1, the indoor unit throttle valve EXV, and the indoor unit 2 back to the compressor 11. If the indoor unit 2 is detected to be cooling in step S3111, it indicates that the first four-way valve ST1 and the second four-way valve ST2 are not reversed. However, it is not ruled out that the first four-way valve ST1 and the second four-way valve ST2 are stuck in the energized state. If the low pressure is lower than the second predetermined value, it indicates that the refrigerant is cut off at the first throttle valve EXV1. The first throttle valve EXV1 is in the closed state, which is opposite to the open state that the first throttle valve EXV1 should respond to. The first throttle valve EXV1 and the second throttle valve EXV2 are reversed.

[0047] If the low pressure is not lower than the second predetermined value, it indicates that refrigerant is returning to the compressor 11. Further control is implemented by de-energizing the first four-way valve ST1, energizing the second four-way valve ST2, closing the first throttle valve EXV1, closing the second throttle valve EXV2, opening the indoor unit throttle valve EXV, and opening the first solenoid valve SV1. The air conditioner then heats up, and the refrigerant sequentially passes through the first four-way valve ST1, the indoor unit 2, and is cut off at the indoor unit throttle valve EXV. If the low pressure is lower than the second predetermined value at this time, it indicates that the first throttle valve EXV1 is functioning correctly. If the low pressure is not lower than the second predetermined value, it indicates that the first throttle valve EXV1 is not completely closed, and refrigerant is returning to the compressor 11 through the first throttle valve EXV1, indicating a fault in the first throttle valve EXV1. Furthermore, compared to the four-way valve opening / closing state in step S31, the change in the four-way valve state causes a change in the refrigerant flow direction, indicating that the first four-way valve ST1 and the second four-way valve ST2 are not only not reversed, but also not stuck, thus improving the accuracy of the four-way valve judgment.

[0048] In step S3112: as Figure 4 As shown, if the indoor unit 2 is heating and the low pressure is lower than the second predetermined value, the first throttle valve EXV1 and the second throttle valve EXV2 are reversed. If the low pressure is not lower than the second predetermined value, the system sequentially checks whether the first throttle valve EXV1 is faulty and whether the second throttle valve EXV2 is faulty, and then outputs that the first four-way valve ST1 and the second four-way valve ST2 are reversed. In step S3112, "sequentially checking whether the first throttle valve EXV1 is faulty and whether the second throttle valve EXV2 is faulty" includes: controlling the first four-way valve ST1 to be energized, the second four-way valve ST2 to be de-energized, the first throttle valve EXV1 to be closed, the second throttle valve EXV2 to be closed, the indoor unit throttle valve EXV1 to be opened, and the first solenoid valve SV1 to be opened; detecting whether the low pressure is lower than the second predetermined value; if the low pressure is not lower than the second predetermined value, the system outputs that the first throttle valve EXV1 is faulty; if the low pressure is lower than the second predetermined value, the system determines whether the second throttle valve EXV2 is faulty.

[0049] In this embodiment, if heating is detected in the indoor unit 2, the refrigerant from the compressor 11 outlet returns to the compressor 11 via the first throttle valve EXV1, the indoor unit 2, the indoor unit throttle valve EXV, the first throttle valve EXV1, and the second four-way valve ST2. This indicates that the first four-way valve ST1 is de-energized, which is the opposite of the state of the first four-way valve ST1 in step S31, meaning that the first four-way valve ST1 and the second four-way valve ST2 are reversed. Furthermore, if the low pressure is detected to be lower than the second predetermined value, the refrigerant is cut off at the first throttle valve EXV1, and the first throttle valve EXV1 is closed, which is the opposite of the open state in step S31. The first throttle valve EXV1 and the second throttle valve EXV2 are reversed. If the low pressure is not lower than the second predetermined value, keep the first four-way valve ST1 energized and the second four-way valve ST2 de-energized. Close the first throttle valve EXV1 and the second throttle valve EXV2, and open the indoor unit throttle valve EXV and the first solenoid valve SV1. The four-way valve status remains unchanged, still in heating mode. The refrigerant from the compressor 11 outlet passes through the first four-way valve ST1, the indoor unit 2, and the indoor unit throttle valve EXV before being cut off by the first throttle valve EXV1. If the low pressure is lower than the second predetermined value, it indicates that the first throttle valve EXV1 is not faulty, and further determine whether the second throttle valve EXV2 is faulty. If the low pressure is not lower than the second predetermined value, it indicates that the first throttle valve EXV1 is open, which is the opposite of the theoretical open state. The first throttle valve EXV1 is faulty, and the first four-way valve ST1 is not faulty.

[0050] In steps S3111 and S3112, "determining whether the second throttle valve EXV2 is faulty" includes: energizing the first four-way valve ST1, de-energizing the second four-way valve ST2, opening the first throttle valve EXV1, closing the second throttle valve EXV2, opening the indoor unit throttle valve EXV, and opening the first solenoid valve SV1; detecting whether the temperature change T is within the specified range; if it is within the specified range, outputting that the second throttle valve EXV2 is fault-free; if the temperature change exceeds the specified range, outputting that the second throttle valve EXV2 is faulty.

[0051] In this embodiment, with the four-way valve, throttle valve, and on / off valve in the aforementioned states, the air conditioning system cools, and the main refrigerant flows sequentially through compressor 11, second four-way valve ST2, outdoor unit 12, first throttle valve EXV1, indoor unit throttle valve EXV1, and indoor unit 2 back to compressor 11. When the second throttle valve EXV2 is closed, if no refrigerant enters compressor 11 from the second throttle valve EXV2 via the first solenoid valve SV1, the temperature change T is within the specified range, indicating that the second throttle valve EXV2 is not faulty. If refrigerant enters compressor 11 from the second throttle valve EXV2 via the first solenoid valve SV1, the temperature change T is large, exceeding the specified range, indicating that the second throttle valve EXV2 is faulty.

[0052] <High voltage not greater than the first predetermined value>

[0053] When the high pressure is not greater than the second predetermined value, there are three situations: the indoor unit 2 is cooling, the indoor unit 2 is heating, and the low pressure is lower than the second preset value and the indoor unit 2 has no abnormal air output. The following is a detailed explanation of the detection process of the four-way valve and the throttle valve in the three situations.

[0054] Internal cooling system

[0055] In step S32, such as Figure 5 As shown, if the indoor unit 2 is cooling and the low pressure is lower than the second predetermined value, the first throttle valve EXV1 and the second four-way valve ST2 are output as faults; if the indoor unit 2 is cooling and the low pressure is not lower than the second predetermined value, the step of determining whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse is executed.

[0056] The steps for determining whether the first throttle valve EXV1 and the second throttle valve EXV2 are reversed include: energizing the first four-way valve ST1, de-energizing the second four-way valve ST2, opening the first throttle valve EXV1, closing the second throttle valve EXV2, opening the indoor unit throttle valve EXV1, and closing the first solenoid valve SV1; detecting whether the low pressure is lower than a second predetermined value; if the low pressure is lower than the second predetermined value, then outputting that the first throttle valve EXV1 and the second throttle valve EXV2 are reversed, and that the first throttle valve EXV1 is not faulty; if the low pressure is not lower than the second predetermined value, determining whether the first throttle valve EXV1 is faulty and whether the second throttle valve EXV2 is faulty.

[0057] In the above manner, if the indoor unit 2 is cooling, it indicates that the second four-way valve ST2 is in a de-energized state, which is the opposite of the energized state that the second four-way valve ST2 should reach in step S1. The second four-way valve ST2 did not respond to the energizing command, that is, the second four-way valve ST2 is faulty. If the low pressure is lower than the second predetermined value, it indicates that no refrigerant returns to the compressor 11, and the refrigerant at the outlet of the outdoor unit 12 is cut off at the first throttle valve EXV1, indicating that the first throttle valve EXV1 is faulty. If the low pressure is not lower than the second predetermined value, it indicates that the first throttle valve EXV1 is in the open state (including being stuck in the open state or opening in response to the normal opening command). Further judgment is made on whether the first throttle valve EXV1 and the second throttle valve EXV2 are reversed. Based on the judgment results of the first throttle valve EXV1 and the second throttle valve EXV2, it is determined whether the first throttle valve EXV1 is fault-free, thus improving the accuracy of the first throttle valve EXV1 fault judgment.

[0058] Furthermore, the system controls the first four-way valve to be energized, the second four-way valve ST2 to be de-energized, the first throttle valve EXV1 to open, the second throttle valve EXV2 to close, the indoor unit throttle valve EXV to open, and the first solenoid valve SV1 to open. The refrigerant from the compressor 11 outlet sequentially passes through the second four-way valve ST2, the outdoor unit 12, the first throttle valve EXV1, the indoor unit throttle valve EXV, and the indoor unit 2 back to the compressor 11. If the low pressure is lower than the second predetermined value, it indicates that the refrigerant is cut off at the first throttle valve EXV1, which is in a closed state, contrary to its expected open state. The first throttle valve EXV1 and the second throttle valve EXV2 are reversed (whether the second throttle valve EXV2 is faulty is unknown and will be determined in a subsequent process). The first throttle valve EXV1 is not faulty. If the low pressure is not lower than the second predetermined value, the system further determines whether the first throttle valve EXV1 and the second throttle valve EXV2 are faulty, improving the completeness and accuracy of the throttle valve determination.

[0059] In this embodiment, the process for determining whether the first throttle valve EXV1 is faulty is as follows: power on the first four-way valve, de-power the second four-way valve ST2, close the first throttle valve EXV1, close the second throttle valve EXV2, open the indoor unit throttle valve EXV1, and open the first solenoid valve SV1; detect whether the low pressure is lower than the second predetermined value. If it is lower than the second predetermined value, the first throttle valve EXV1 is not faulty; if it is not lower than the second predetermined value, the EXV1 body is faulty.

[0060] The procedure for determining whether the second throttle valve EXV2 is faulty and Figure 2 , Figure 3 The process shown is the same and will not be repeated here. The determination of whether the second throttle valve EXV2 is faulty can be connected after the determination process of whether the first throttle valve EXV1 is faulty or not. This allows the second throttle valve EXV2 to be determined regardless of whether the first throttle valve EXV1 is faulty, thus improving the accuracy of the determination.

[0061] <Internal mechanism of heat>

[0062] In step S32, as Figure 6 As shown, if the indoor unit 2 is heating and the low pressure is lower than the second predetermined value, the first throttle valve EXV1 and the first four-way valve ST1 are faulty. If the indoor unit 2 is heating and the low pressure is not lower than the second predetermined value, it is determined whether the first throttle valve and the second throttle valve are connected in reverse, whether the first throttle valve is faulty, and whether the second throttle valve is faulty.

[0063] Determining whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse, whether the first throttle valve EXV1 is faulty, and whether the second throttle valve EXV2 is faulty includes:

[0064] The system controls the first four-way valve ST1 to de-energize, the second four-way valve ST2 to energize, the first throttle valve EXV1 to open, the second throttle valve EXV2 to close, the indoor unit throttle valve EXV internally to open, and the first solenoid valve SV1 to close. It then checks whether the indoor unit 2 is heating. When the indoor unit 2 is heating, it checks whether the low pressure is lower than a second preset value. If the low pressure is lower than the second preset value, it outputs that the first throttle valve EXV1 and the second throttle valve EXV2 are reversed. If the low pressure is not lower than the second preset value, it controls the first four-way valve ST1 to energize, the second four-way valve ST2 to de-energize, the first throttle valve EXV1 to close, the second throttle valve EXV2 to close, the indoor unit throttle valve EXV internally to open, and the first solenoid valve SV1 to open. It then checks again whether the low pressure is lower than the second preset value. If the low pressure is lower than the second preset value, it outputs that the first throttle valve EXV1 is fault-free and determines whether the second throttle valve EXV2 is faulty. If the low pressure is not lower than the second preset value, it outputs that the first throttle valve EXV1 is faulty.

[0065] In the above manner, if the indoor unit 2 is heating, it indicates that the first four-way valve ST1 is in a de-energized state, which is the opposite of the energized state that the first four-way valve ST1 should reach in step S1. The first four-way valve ST1 does not respond to the energizing command, that is, the first four-way valve ST1 is faulty. If the low pressure is lower than the second predetermined value, it indicates that no refrigerant returns to the compressor 11, and the refrigerant at the outlet of the indoor unit 2 is cut off at the first throttle valve EXV1, indicating that the first throttle valve EXV1 is faulty. If the low pressure is not lower than the second predetermined value, it indicates that the first throttle valve EXV1 is in the open state (including being stuck in the open state or opening in response to the normal opening command). Further judgment is made on whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse. Based on the judgment result of whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse, if they are not connected in reverse, further judgment is made on whether the first throttle valve EXV1 is faulty and whether the second throttle valve EXV2 is faulty, which improves the accuracy of the first throttle valve EXV1 fault judgment.

[0066] Furthermore, by controlling the first four-way valve ST1 to de-energize, the second four-way valve ST2 to energize, the first throttle valve EXV1 to open, the second throttle valve EXV2 to close, the indoor unit throttle valve EXV to open, and the first solenoid valve SV1 to close; and by detecting whether the indoor unit 2 is heating, it can be verified again that a malfunction in the first four-way valve ST1 causes the indoor unit 2 to heat, thus improving the accuracy of the judgment. By controlling the opening and closing states of the first throttle valve EXV1 and the second throttle valve EXV2 to be opposite, and based on the refrigerant flow direction and low-pressure detection results under the opposite opening and closing states of the first throttle valve EXV1 and the second throttle valve EXV2, it is possible to determine whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse. Specifically, under normal circumstances, the refrigerant at the outlet of compressor 11 returns to compressor 11 sequentially through the first four-way valve ST1, indoor unit 2, indoor unit throttle valve EXV, first throttle valve EXV1, outdoor unit 12, and second four-way valve ST2. If the low pressure is lower than the predetermined value, it indicates that the refrigerant has not returned to compressor 11. The refrigerant at the outlet of indoor unit throttle valve EXV is cut off at the first throttle valve EXV1, that is, the first throttle valve EXV1 is closed, which is opposite to the opening state that the first throttle valve EXV1 should respond to. The first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse. Furthermore, if the low pressure is not lower than the second predetermined value, the air conditioning system will cool by controlling the first four-way valve ST1 to be energized, the second four-way valve ST2 to be de-energized, the first throttle valve EXV1 to be closed, the second throttle valve EXV2 to be closed, the indoor unit throttle valve EXV to be opened, and the first solenoid valve SV1 to be opened. The refrigerant at the outlet of compressor 11 will be cut off at the first throttle valve EXV1 via the second four-way valve ST2 and the outdoor unit 12. If the low pressure is lower than the second predetermined value, it indicates that the first throttle valve EXV1 is in a closed state and the first throttle valve EXV1 is not faulty. If the low pressure is not lower than the second predetermined value, it indicates that refrigerant may have returned to compressor 11 from the indoor unit throttle valve EXV, indoor unit 2, first throttle valve EXV1, and second four-way valve ST2. The first throttle valve EXV1 or the second throttle valve EXV2 is faulty and not closed. The refrigerant returns to compressor 11 via the second throttle valve EXV2 and the first solenoid valve SV1. Therefore, by continuing to determine whether the second throttle valve EXV2 is faulty, the fault condition of the second throttle valve EXV2 is determined, and the fault detection of the first throttle valve EXV1, the second throttle valve EXV2 and the first four-way valve ST1 is realized, ensuring the operational reliability of the air conditioning system.

[0067] In this embodiment, the process for determining whether the second throttle valve EXV2 is faulty is the same as... Figure 2 , Figure 3 The process shown is the same, so it will not be repeated here.

[0068] <Whether the low pressure is below the second predetermined value and whether there are any abnormalities in the airflow from the indoor unit>

[0069] In a preferred embodiment of the present invention, such as Figure 7As shown, in step S33, if the low pressure is not lower than the second predetermined value, determining whether the second throttle valve EXV2 is faulty includes:

[0070] Control the closure of the first throttle valve EXV1 and the second throttle valve EXV2, and open the indoor unit throttle valve EXV1 and the first solenoid valve SV1; detect whether the low pressure is lower than the second predetermined value; execute steps S331 and S332 respectively according to the low pressure detection result;

[0071] S331: If the low pressure is lower than the second predetermined value, it indicates that no refrigerant flows out through the second throttle valve EXV2, the output of the second throttle valve EXV2 is fault-free, and it is determined whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse.

[0072] Specifically, determining whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse includes: controlling the first throttle valve EXV1 to close, the second throttle valve EXV2 to open, the indoor unit throttle valve EXV1 and the first solenoid valve SV1 to close, and the second solenoid valve SV2 to close; and then checking again whether the low pressure is lower than the third predetermined value.

[0073] If the low pressure is not lower than the third predetermined value, the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse.

[0074] If the low pressure is lower than the third predetermined value, it indicates that the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse, and it is determined whether the first throttle valve EXV1 is faulty. Further, determining whether the first throttle valve EXV1 is faulty includes: controlling the first throttle valve EXV1 and the second throttle valve EXV2 to open, the indoor unit throttle valve EXV1 to close, the first solenoid valve SV1 to open, and the second solenoid valve SV2 to close; and detecting whether the low pressure is lower than the third predetermined value; if the low pressure is lower than the third predetermined value, it outputs that the first throttle valve EXV1 is faulty; if the low pressure is not lower than the third predetermined value, it outputs that the first throttle valve EXV1 is not faulty. In this embodiment, when the second throttle valve EXV2 is not faulty, further determining whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse and whether the first throttle valve EXV1 is faulty improves the accuracy of the determination.

[0075] Step S332: If the low pressure is not lower than the second predetermined value, output a fault message for the second throttle valve EXV2 (the second throttle valve EXV2 is stuck in the open state), and determine whether the first throttle valve EXV1 is faulty. Specifically, determining whether the first throttle valve EXV1 is faulty includes: controlling the opening of the first throttle valve EXV1, the second throttle valve EXV2, and the first solenoid valve SV1; closing the indoor unit throttle valve EXV1 and the second solenoid valve SV2; the refrigerant at the compressor 11 outlet returns to the compressor 11 via the second four-way valve ST2, the outdoor unit 12, the first throttle valve EXV1, the second throttle valve EXV2, and the first solenoid valve SV1; and checking again whether the low pressure is lower than the third predetermined value.

[0076] If the low pressure is lower than the third predetermined value, it indicates that the refrigerant is cut off at the first throttle valve EXV1, and the first throttle valve EXV1 is faulty.

[0077] If the low pressure is not lower than the third predetermined value, the following methods are used to determine whether the first throttle valve EXV1 is faulty or whether the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse. Specifically, determining whether the first throttle valve EXV1 is faulty includes: controlling the first throttle valve EXV1 and the indoor unit throttle valve EXV to be closed, the second throttle valve EXV2 to be open, the second solenoid valve SV2 to be open, and the first solenoid valve SV1 to be closed, so that there is no refrigerant flow, and detecting whether the low pressure is lower than the third predetermined value; if the low pressure is lower than the third predetermined value, it indicates that no refrigerant flows through the first throttle valve EXV1, the first throttle valve EXV1 is in a closed state, consistent with the expected response state, and the output indicates that the first throttle valve EXV1 is fault-free; if the low pressure is not lower than the third predetermined value, it indicates that refrigerant flows out of the first throttle valve EXV1 and returns to the compressor 11 through the second solenoid valve SV2, and the output indicates that the first throttle valve EXV1 and the second throttle valve EXV2 are connected in reverse. In this embodiment, when the second throttle valve EXV2 fails, the control conditions enable the determination of whether the first throttle valve EXV1 is faulty, regardless of whether the low pressure is lower than the third predetermined value. This improves the accuracy of the determination and enhances the stability of the air conditioning system operation.

[0078] It should be noted that in this embodiment, low pressure refers to the pressure at the return end of compressor 11, and high pressure refers to the pressure at the discharge end of compressor 11. The first predetermined value is greater than the second predetermined value, and the second predetermined value is greater than the third predetermined value. The solenoid valve can be any other control switch device, not limited to a solenoid valve. Furthermore, when the first four-way valve ST1 and the second four-way valve ST2 are stuck at the DC end, their corresponding compressor frequency and fan speed are lower than those under other conditions, to ensure the stable operation of the air conditioning system when the first four-way valve ST1 and the second four-way valve ST2 are stuck at the DC end. Furthermore, although this embodiment shows the above-described flowchart and the defined judgment sequence, those skilled in the art will understand that, by adjusting the opening and closing states of the first four-way valve ST1, the second four-way valve ST2, the first throttle valve EXV1, and the second throttle valve EXV1, the theoretical flow direction of the refrigerant can be obtained. Combined with low-pressure detection, the actual flow direction of the refrigerant can be obtained. Based on the comparison results of the actual flow direction and the theoretical flow direction, whether they are the same or opposite, the actual response state of the four-way valve and the throttle valve can be deduced. Based on this, the judgment results of whether the first four-way valve ST1 and the second four-way valve ST2 are inserted in reverse, whether the first throttle valve EXV1 and the second throttle valve EXV2 are inserted in reverse, and whether the first throttle valve EXV1 and the second throttle valve EXV2 are faulty can be obtained. Those skilled in the art can adjust the order of the above judgment process, or add or reduce some judgment processes, or adjust the opening and closing states of the throttle valve, solenoid valve, and four-way valve in some judgment processes according to the actual situation.

[0079] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for inspecting a multi-split air conditioning system, characterized in that, The multi-split air conditioning system includes: a compressor, a first four-way valve, a second four-way valve, an outdoor heat exchanger, an indoor heat exchanger, a first throttling valve, a second throttling valve, an indoor unit throttling valve, a first branch pipe, and a first solenoid valve; wherein... The compressor outlet is connected to the d1 port of the first four-way valve and the d2 port of the second four-way valve, respectively, and the compressor inlet is connected to the s1 port of the first four-way valve and the s2 port of the second four-way valve, respectively. The C1 port of the first four-way valve is connected to the indoor heat exchanger, and the C2 port of the second four-way valve is connected to the outdoor heat exchanger. The e1 port of the first four-way valve is connected to the s1 port; the e2 port of the second four-way valve is connected to the s2 port. The outdoor heat exchanger is connected to the indoor heat exchanger, and the first throttling valve and the indoor unit throttling valve are connected in sequence between the outdoor heat exchanger and the indoor heat exchanger. The first end of the first branch pipe is connected to the compressor, and the second end of the first branch pipe is connected between the first throttle valve and the indoor unit throttle valve; the first solenoid valve and the second throttle valve are sequentially provided from the first end of the first branch pipe to the second end of the first branch pipe; The temperature detection module is used to detect the temperature T of the refrigerant between the second throttle valve and the first solenoid valve; The commodity inspection method includes the following steps: Step S1: Power on the first four-way valve and the second four-way valve, close the first solenoid valve, and open the first throttle valve, the second throttle valve, and the indoor unit throttle valve; Step S2: Determine whether the high voltage is greater than the first predetermined value; Step S31: If the high pressure is greater than the first predetermined value, then control the first four-way valve to be energized and the second four-way valve to be de-energized, close the second throttle valve, keep the first throttle valve open and the first solenoid valve closed; detect the cooling and heating status of the indoor unit and detect whether the low pressure is lower than the second predetermined value; Step S311: Based on the refrigeration and heating status of the indoor unit and whether the low pressure is lower than the second predetermined value, determine whether the first four-way valve and the second four-way valve are connected in reverse, and determine whether the first throttle valve and the second throttle valve are connected in reverse; and under the conditions of the first four-way valve and the second four-way valve being connected in reverse and not connected in reverse, determine whether the first throttle valve is faulty and whether the second throttle valve is faulty respectively. Step S32: If the high pressure is not greater than the first predetermined value, detect the cooling and heating status of the indoor unit and detect whether the low pressure is lower than the second predetermined value to determine whether the first four-way valve or the second four-way valve is faulty, and determine whether the first throttle valve is faulty; determine whether the first throttle valve and the second throttle valve are connected in reverse and determine whether the second throttle valve is faulty; wherein, the low pressure is the pressure at the return end of the compressor, the high pressure is the pressure at the discharge end of the compressor, and the first predetermined value is greater than the second predetermined value.

2. The commercial inspection method for a multi-split air conditioning system according to claim 1, characterized in that, In step S311, the step of "determining whether the first four-way valve and the second four-way valve are connected in reverse, and determining whether the first throttle valve and the second throttle valve are connected in reverse, based on the indoor unit's refrigeration and heating status and whether the low pressure is lower than the second predetermined value; and determining whether the first throttle valve is faulty and whether the second throttle valve is faulty under the conditions of the first four-way valve and the second four-way valve being connected in reverse and not connected in reverse" includes: Step S3111: If the indoor unit is refrigerated and the low pressure is lower than the second predetermined value, output that the first throttle valve and the second throttle valve are reversed; if the low pressure is not lower than the second predetermined value, sequentially determine whether the first throttle valve is faulty, determine whether the second throttle valve is faulty, and output that the first four-way valve and the second four-way valve are not reversed. The step S3111 or the step S311 in which "sequentially determine whether the first throttle valve is faulty and determine whether the second throttle valve is faulty" includes: The system controls the first four-way valve to de-energize, the second four-way valve to energize, the first throttle valve to close, the second throttle valve to close, the indoor unit throttle valve to open, and the first solenoid valve to open; and detects whether the low pressure is lower than a second predetermined value; If the low pressure is lower than the second predetermined value, the first throttle valve is output as fault-free, and the second throttle valve is determined as faulty; if the low pressure is not lower than the second predetermined value, the first throttle valve is output as faulty.

3. The commercial inspection method for a multi-split air conditioning system according to claim 2, characterized in that, In step S311, the step of "determining whether the first four-way valve and the second four-way valve are connected in reverse, and determining whether the first throttle valve and the second throttle valve are connected in reverse, based on the indoor unit's refrigeration and heating status and whether the low pressure is lower than the second predetermined value; and determining whether the first throttle valve is faulty and whether the second throttle valve is faulty under the conditions of the first four-way valve and the second four-way valve being connected in reverse and not connected in reverse" includes: Step S3112: If the internal unit is heating and the low pressure is lower than the second predetermined value, output that the first throttle valve and the second throttle valve are reversed; if the low pressure is not lower than the second predetermined value, sequentially determine whether the first throttle valve is faulty, determine whether the second throttle valve is faulty, and output that the first four-way valve and the second four-way valve are reversed. In step S3112 or step S311, the step of "sequentially determining whether the first throttle valve is faulty and determining whether the second throttle valve is faulty" includes: The system controls the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be closed, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened; it also detects whether the low pressure is lower than the second predetermined value. If the low pressure is not lower than the second predetermined value, then the first throttle valve is faulty; if the low pressure is lower than the second predetermined value, then the first throttle valve is not faulty, and it is determined whether the second throttle valve is faulty.

4. The commercial inspection method for a multi-split air conditioning system according to any one of claims 1 to 3, characterized in that, The "determining whether the second throttle valve is faulty" includes: The system controls the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be opened, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened. Check whether the temperature change at temperature T is within the specified range; If it is within the specified range, the output indicates that the second throttle valve is fault-free; If the temperature change exceeds the specified range, a fault is output for the second throttle valve.

5. The commercial inspection method for a multi-split air conditioning system according to claim 1, characterized in that, In step S32, if the indoor unit is refrigerated and the low pressure is lower than the second predetermined value, the first throttle valve fault and the second four-way valve fault are output. If the internal cooling system is refrigerated and the low pressure is not lower than the second predetermined value, then the step of determining whether the first throttle valve and the second throttle valve are connected in reverse is executed.

6. The commercial inspection method for a multi-split air conditioning system according to claim 5, characterized in that, The steps for determining whether the first throttle valve and the second throttle valve are connected in reverse include: The system controls the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be opened, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be closed; it also detects whether the low pressure is lower than the second predetermined value. If the low pressure is lower than the second predetermined value, the first throttle valve and the second throttle valve are reversed, and the first throttle valve is fault-free; If the low pressure is not lower than the second predetermined value, it is determined whether the first throttle valve and the second throttle valve are faulty.

7. The commercial inspection method for a multi-split air conditioning system according to claim 1, characterized in that, In step S32, if the internal unit heats up and the low pressure is lower than the second predetermined value, output the first throttle valve fault and the first four-way valve fault. If the internal heating is activated and the low pressure is not lower than the second predetermined value, then determine whether the first throttle valve and the second throttle valve are connected in reverse, whether the first throttle valve is faulty, and whether the second throttle valve is faulty.

8. The commercial inspection method for a multi-split air conditioning system according to claim 7, characterized in that, The determination of whether the first throttle valve and the second throttle valve are connected in reverse, whether the first throttle valve is faulty, and whether the second throttle valve is faulty includes: The system controls the first four-way valve to de-energize, the second four-way valve to energize, the first throttle valve to open, the second throttle valve to close, the indoor unit throttle valve to open, and the first solenoid valve to close. Detect whether the indoor unit is heating; when the indoor unit is heating, detect whether the low pressure is lower than the second preset value. If the low pressure is lower than the second predetermined value, then the first throttle valve and the second throttle valve are connected in reverse. If the low pressure is not lower than the second predetermined value, then control the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be closed, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened; then check again whether the low pressure is lower than the second predetermined value; If the low pressure is lower than the second predetermined value, the first throttle valve is deemed to be fault-free; if the low pressure is not lower than the second predetermined value, the second throttle valve is deemed to be faulty.

9. The commercial inspection method for a multi-split air conditioning system according to any one of claims 5 to 8, characterized in that, The "determining whether the second throttle valve is faulty" includes: The system controls the first four-way valve to be energized, the second four-way valve to be de-energized, the first throttle valve to be opened, the second throttle valve to be closed, the indoor unit throttle valve to be opened, and the first solenoid valve to be opened. Check whether the temperature change at temperature T is within the specified range; If it is within the specified range, the second throttle valve output is fault-free; If the temperature change exceeds the specified range, the second throttle valve will be flagged as faulty.

10. A multi-split air conditioning system, characterized in that, A commercial inspection method for a multi-split air conditioning system that implements any one of claims 1 to 9.

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