May 23, 2025
The main manifestation of air source heat pump compressor faults is "failure to start", or "stuck cylinder" or "stuck shaft", which we generally call "stall". Heat pump compressor stall is a fatal fault that can only be solved by replacing the compressor. The most direct manifestation of compressor stall is that the compressor cannot start, or even the motor burns out, or the thermal protector frequently operates when it starts under certain conditions. For inverter compressors, it manifests as the speed cannot be increased and the inverter drive overload protection. Below we will explain in detail the specific causes of air source heat pump compressor stall:
1. Heat pump compressor motor damage
(1) The motor is burned due to incorrect wiring of the compressor terminal;
(2) System refrigerant leakage; because the high-pressure gas of the rotary compressor is responsible for taking away the heat generated by the motor while discharging the compressor. If the system refrigerant leaks, only a small amount of high-pressure gas will be discharged from the compressor, so the heat generated by the heat pump compressor motor when it is powered on will continue to accumulate. In the long run, it will cause the heat pump compressor motor to burn out.
(3) When the compressor is blocked, the motor should be excluded as much as possible. Therefore, the insulation resistance of the motor and the windings of the main and auxiliary coils should be measured first to determine whether the motor is burned.
2. Capacitor problem of heat pump compressor
(1) The capacitor is damaged (short circuit, open circuit);
(2) The capacitor specifications do not match the compressor.
(3) This item is only applicable to single-phase compressors. Because three-phase compressors use three-phase induction motors, which generate a rotating magnetic field by passing three-phase alternating current through the stator core, so capacitors are not required.
3. Frequent thermal protection of heat pump compressors
(1) The thermal protector is abnormal; refer to the performance diagram and text description of this item in the specification provided by the compressor manufacturer.
(2) The power line wiring is unreasonable (the wiring of the compressor terminal is incorrect, or the inverter of the inverter air conditioner is running in a phase loss: that is, check the current between the three phases to see if there is a short circuit or open circuit), low voltage starting.
(3) The system is started before the high and low pressures are balanced. Generally, it is required to restart the system at least 3 minutes after shutting down. It is also possible that the capillary flow of the system is too small, so the high and low pressures cannot be balanced as soon as possible.
