초록 ▼

Compressor discharge temperature, ambient outdoor air temperature and thermal load are used as control parameters for controlling the expansion valve setting and indoor fan speed. Diagnostics monitor a feedback signal from the fan motor to detect fan over-speed and increased speed due to decreased a

Compressor discharge temperature, ambient outdoor air temperature and thermal load are used as control parameters for controlling the expansion valve setting and indoor fan speed. Diagnostics monitor a feedback signal from the fan motor to detect fan over-speed and increased speed due to decreased air flow caused by a dirty indoor air filter. Discharge pressure of the compressor is monitored to detect a blocked outdoor fan. The difference between actual and optimum compressor discharge temperatures and suction pressure of the compressor are monitored to detect a stuck-closed expansion valve or low refrigerant charge. Compressor “short-cycling”is limited to prevent reduced reliability of the compressor. The difference between compressor discharge temperature and outdoor coil temperature is measured before and after startup to detect compressor failure.

대표청구항 ▼

A controller for a heat pump system which operates in heating and cooling modes and is of the type having a compressor for discharging refrigerant through an expansion valve (EXV) into a heat exchanger, comprising: a first sensor for sensing a first parameter indicative of the actual temperature of

A controller for a heat pump system which operates in heating and cooling modes and is of the type having a compressor for discharging refrigerant through an expansion valve (EXV) into a heat exchanger, comprising: a first sensor for sensing a first parameter indicative of the actual temperature of the refrigerant discharged from said compressor; and at least one control processor having means for effecting a diagnostic procedure that: (a) determines an optimum discharge temperature; (b) generates a differential temperature by taking the difference between the actual discharge temperature and the optimum discharge temperature; and (c) executes a low pressure diagnostic procedure if said differential temperature is less than a first parameter.