Protection method for preventing superheat during heating of multi-connection air conditioning unit

Abstract

The invention discloses a protection method for preventing superheat during the heating of a multi-connection air conditioning unit, which comprises the following steps of: measuring the temperature Tm in the middle of an indoor heat exchanger (3) in each indoor machine; when Tm is equal to or greater than 56 DEG C and smaller than 60 DEG C, enforcing an outdoor fan to stop and enforcing an indoor fan to run under a high wind level as well as commanding a frequency conversion compressor (2) of each outdoor machine to run under a down frequency by a main controller; and when Tm reaches 60 DEG C, commanding the frequency conversion compressor (2) of each outdoor machine to directly reduce the frequency to a fixed value and to run under the fixed frequency, stopping a fixed frequency compressor (1) of one outdoor machine, and then stopping a running fixed frequency compressor (1) of one outdoor machine every 10 seconds by the main controller. Through the protection method, high voltage faults can be avoided, the system can run stably and the damage of the unit is avoided.

Description

technical field [0001] The invention relates to a multi-connected air-conditioning unit, in particular to a protection method for preventing overheating when the multi-connected air-conditioning unit is heating. Background technique [0002] The multi-connected air conditioner unit in the prior art includes a plurality of outdoor units connected in parallel, a plurality of indoor units connected in parallel, and two refrigerant circulation main pipes connecting each indoor unit and each outdoor unit. Each outdoor unit includes a fixed-frequency compressor, a variable-frequency compressor, an outdoor heat exchanger (evaporator) and a throttling device. The two compressors are connected in parallel, and the outlets of the two compressors are connected to a refrigerant circulation main pipe. The other refrigerant circulation main pipe communicates with one end of the throttling device, the other end of the throttling device communicates with one end of the outdoor heat exchange...

AI Technical Summary

Problems solved by technology

[0003] Generally speaking, the higher the coil temperature of the indoor heat exchanger of the indoor unit of the multi-connected air conditioner unit, the better, so that the heating effect can be quickly achieved, but everything has a limit. Once the coil temperature is too high, it will be overheated. It will cause adverse effects. Specifically, when the multi-connected air conditioner unit is running, due to certain circumstances, such as the room where an indoor unit is located has a good sun angle, long sun exposure time, and high indoor temperature, or when the unit is off work, the unit Most of the indoor units are turned off, and the indoor units in the overtime room are turned on, so that the refrigerant is concentrated in this room, etc., which will cause the temperature of the indoor unit coil to overheat. Once the indoor unit coil is overheated, it will make the coil The gaseous refrigerant in the pipe cannot release heat and liquefy, which will lead to a large amount of gaseous refrigerant in the air conditioning system, so that the system air pressure will continue to increase, resulting in high pressure failure of the unit, unstable operation, and even damage to the unit

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