Greenheck Fan 473501 manual Troubleshooting - Refrigeration Circuit, Symptom, Possible Cause

Troubleshooting – Refrigeration Circuit

Symptom	Possible Cause	Corrective Action
	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
Low suction		refrigerant.
pressure
	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	Adjust valve for proper superheat or replace the
	valve too small.	expansion valve if too small or defective.
	Moisture in system.	Reclaim refrigerant, check for leaks, recharge.
	Insufficient refrigerant charge.	Check subcooling, check for leak. Repair leak and
		add refrigerant.
	Defective or improperly adjusted expansion	Check superheating and adjust thermal expansion
Low discharge	valve.	valve.
pressure
	Low suction pressure.	See “Low suction pressure”.
	Faulty condenser temperature controls.	Check condenser controls and reset to obtain
		desired condensing temperature.
	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.
Compressor	Defective expansion valve.	Check thermal expansion valve and superheat.
short cycles	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.

34 Model ERCH-HP Energy Recovery Unit