Method for detecting welding blockage of electronic outdoor unit expansion valves of multi-coupled air-conditioning unit

Abstract

The invention discloses a method for detecting the welding blockage of electronic outdoor unit expansion valves of a multi-coupled air-conditioning unit. The method includes the following steps: (a) a compressor (1) of the outdoor unit is operated under the heating mode for at least two minutes; (b) the difference between suction temperature and outdoor temperature, the difference between the temperature of the middle section of the coil of an outdoor heat exchanger (2) and the outdoor temperature and the difference between defrosting temperature and the outdoor temperature are detected and calculated; (c) whether all the differences are less than or equal to 3 is judged and a low-voltage outdoor unit pressure switch (3) is switched off; if the conditions are met, then the complete welding blockage of the electronic outdoor unit expansion valve (4) is determined, and the detection process is terminated; and if the conditions are not met, then the next step is carried out; (d) the compressor (1) of the outdoor unit is continuously operated for at least four minutes; (e) whether the defrosting temperature is lower than or equal to negative 15 DEG C is judged and the low-voltage outdoor unit pressure switch (3) is switched off, and if the conditions are met, then the partial welding blockage of the electronic outdoor unit expansion valve (4) is determined. The detection method is rapid, convenient and accurate.

Description

technical field [0001] The invention relates to a multi-connected air-conditioning unit, in particular to a method for detecting whether an electronic expansion valve of an external unit of the multi-connected air-conditioning unit is welded and blocked. Background technique [0002] The multi-connected air conditioner unit in the prior art includes one or more outdoor units, a plurality of indoor units connected in parallel, and two refrigerant circulation main pipes connecting each indoor unit and each outdoor unit. If there is one outdoor unit, the outdoor unit is connected to multiple indoor units connected in parallel through two refrigerant circulation main pipes; if there are multiple outdoor units, multiple outdoor units are connected in parallel, and the parallel outdoor units pass through two refrigerant circulation main pipes Connect with the indoor units connected in parallel. [0003] Each outdoor unit includes a compressor, an oil separator, a four-way reversi...

AI Technical Summary

Problems solved by technology

However, the electronic expansion valve of the external unit is manually welded to the pipeline of the unit, and the inner diameter of the inlet and outlet pipes of the electronic expansion valve of the external unit does not exceed 6mm. In this way, welding blockage will inevitably occur. condition, it will cause the front end of the electronic expansion valve of the external unit to report a high pressure fault, and the rear end to report a low pressure fault

Since the electronic expansion valve of the external unit is welded to the system pipe, it is impossible to directly detect whether there is a welding blockage. We can only check other fault causes one by one, and finally determine the welding blockage if they are not

However, there are many reasons why the air conditioner reports high-voltage and low-voltage failures, such as insufficient fan speed of the external unit and internal unit, blockage of the coil of the heat exchanger, dust on the coil of the heat exchanger, which makes the heat exchange insufficient, and the heat exchanger The capillary at the end of the coil is blocked, etc. Therefore, every time a welding blockage causes a high-pressure or low-voltage fault, the technician often spends a lot of time checking one by one to finally find out and determine the cause of the welding blockage, so the detection process is cumbersome. ,Time-consuming

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