Filter
Top Products
34
Model ERCH-HP Energy Recovery Unit
Troubleshooting – Refrigeration Circuit
Symptom Possible Cause Corrective Action
Low suction
pressure
Refrigerant undercharge. Check pressures and subcooling.
Blower running backward.
Interchange any two wires from 3 phase
disconnect.
Loose blower, pulley or belts. Check drive pulley alignment, belt tension.
Low entering air temperature (low load condition). Check entering air wet bulb conditions.
Refrigerant leak.
Check system for leaks. Repair leaks and add
refrigerant.
Evaporator dirty or iced up or airflow restricted.
Check defrost system. Clean the coil.
Check fan operation. Check airflow.
Plugged liquid line filter-drier. Replace filter-drier.
Improper suction pressure regulator setting. Check setting and correct as required.
Expansion valve defective, superheat too high, or
valve too small.
Adjust valve for proper superheat or replace the
expansion valve if too small or defective.
Moisture in system. Reclaim refrigerant, check for leaks, recharge.
Low discharge
pressure
Insufficient refrigerant charge.
Check subcooling, check for leak. Repair leak and
add refrigerant.
Defective or improperly adjusted expansion
valve.
Check superheating and adjust thermal expansion
valve.
Low suction pressure. See “Low suction pressure”.
Faulty condenser temperature controls.
Check condenser controls and reset to obtain
desired condensing temperature.
Compressor
short cycles
Thermostat location or malfunction. Check thermostat, check heat anticipator setting.
Improper refrigerant charge. Check subcooling, verify superheat.
Defective high or low pressure control. Check high or low pressure switch.
Liquid floodback. Possible tight bearings.
Defective expansion valve. Check thermal expansion valve and superheat.
Poor air distribution. Check ductwork for recirculating.
High discharge pressure. See “High discharge pressure”.
Leaking discharge valves in compressor. See “High suction pressure”.
Low airflow at evaporator(s). Check blower operation and airstream restrictions.
Incorrect unit selection (oversized). Contact factory.
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.