Principle and maintenance method of air conditioner pressure protector

Principle and maintenance method of air conditioner pressure protector

In addition to window air-conditioning units, many air-conditioning systems use high-pressure and (or) low-pressure pressure protectors to protect the compressor in the event of a system failure. During the normal operation of the device, these controllers are in a normal "sleep" state and rarely "active". However, if the circuit-E is open or intermittently open, they will come into play and prevent the compressor from working.

The high pressure protection cryo is located in the compressor high pressure discharge line, which can monitor discharge pressure. The contact of the controller is closed under normal conditions, and it is connected in series with the power relay or the contactor coil that controls the compressor.

　　 If the exhaust pressure of the system exceeds a predetermined range due to a failure (such as a condenser fan motor failure or a blocked air flow in the condenser), overpressure may be caused. This overvoltage will activate the controller, causing the controller contacts to trip and shut down the compressor. When the pressure returns to normal, the protector cannot automatically reset, and the reset button must be pressed to resume work.

　　 When the high-pressure pressure protector is activated, the composite pressure gauge should be connected to the system to monitor the pressure readings to analyze the cause of activation. All obvious faults (such as insufficient air flow in the condenser) should be eliminated. Just like removing dust and residue from the condenser coil or tightening a loose belt, the work is simple.

　　 low-pressure pressure protector is located in the compressor suction line to prevent the compressor from continuing to work in the event of abnormal operation (such as insufficient refrigerant injection). When using a high-voltage pressure protector, the contacts of the low-voltage switch are usually closed and connected in series with the power relay coil or contactor.

　　 Air-conditioning systems with complete or partial loss of refrigerant may not work at all, or only work for a few seconds until the low-pressure pressure protector cuts off the current to the relay coil. The composite pressure gauge connected to the unit will display the pressure value of the suction line.

　　The pressure protector whose contact trips may fail completely or periodically. When this happens, the compressor will not work at all, or it will not work continuously even if the refrigerant is sufficient or the various pressures are normal. If you encounter this kind of failure, a simple way is to temporarily jump over a piece of wire over the faulty controller contact, and limit the failure to one or several other pressure controllers. If the isolated controller is faulty, the compressor will resume operation.

　　 Pressure protectors are generally not repairable on site and must be replaced. Unfortunately, this may require exhausting all refrigerant in the system. if possible. The refrigerant storage system can be used to store the refrigerant to prevent the refrigerant from spreading into the air