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

Troubleshooting – Refrigeration Circuit

Symptom	Possible Cause	Corrective Action
	Low oil level (trapped oil in evaporator or suction	Thoroughly defrost evaporator. After defrost,
		observe level, add oil. Check for leaks. Check lines
	line).
		for proper slope and traps.
	Excessive liquid refrigerant in the crankcase.	Adjust expansion valve for higher superheat. Check
		crankcase heater.
Low or no
	Worn oil pump.	Replace the oil pump.
oil pressure
	Worn compressor bearings.	Replace the compressor.
	Loose fitting on oil line or pump housing gasket	Check and tighten system. Check bottom plate or
	leaking.	compressor.
	Compressor short cycling.	Check low pressure control setting.
	Refrigerant leak.	Check system for leaks. Repair leaks and add
		refrigerant.
	Short cycling.	Check low pressure control settings.
Compressor
		Check thermal expansion valve setting. Check for
loses oil	Refrigerant flood back.
		refrigerant overcharge.
	Improper piping or traps.	Verify proper piping slopes.
	Reheat flush cycle inadequate.	Contact factory.
	Refrigeration undercharged.	Check subcooling.
	Dirty filter or evaporator coil.	Check filter, coil and airflow.
	Dirty or clogged condenser coil.	Check coil and airflow.
	Air or other non-condensables in system.	Check equalized high side pressure with equivalent
Running cycle is		outdoor temperature.
too long or unit
	Defective compressor.	See “High suction pressure”.
operates
continuously	Restriction in suction and liquid line.	Check for restrictions in refrigerant circuit.
	Control contacts stuck.	Check wiring.
	Excessive load.	Add more equipment or reduce room load.
	Too low of a system thermostat setting or	Adjust or replace thermostat.
	defective thermostat.
Liquid line	Refrigerant undercharge.	Adjust the charge by subcooling.
is too hot	High discharge pressure.	See “High discharge pressure”.
Liquid line is	Restriction in liquid line.	Clear restriction upstream of point of frosting.
frosted or wet
	Insufficient evaporator airflow.	Check airflow, check filters, check drive for loose
		parts or belts.
Suction line
is frosting	Restriction in suction or liquid line.	Restriction upstream of point of frosting.
	Malfunctioning or defective expansion valve.	Check bulb of thermal expansion valve.
Frost on	Hot gas bypass valve not functioning properly.	Check valve. If defective, replace.
evaporator coil	Manual hot gas bypass valve closed.	Open valve.

Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.

Model ERCH-HP Energy Recovery Unit 35