Greenheck ERCH - Energy Recovery Unit with Packaged DX (468151) - Manual (Page 49)

49
Energy Recovery Unit with Packaged DX
Troubleshooting - General Refrigeration Circuit
Symptom Possible Cause Corrective Action
Low or no
oil pressure
Low oil level (trapped oil in evaporator or
suction line) .
Thoroughly defrost evaporator . After defrost,
observe level, add oil . Check for leaks . Check
lines for proper slope and traps .
Excessive liquid refrigerant in the crankcase .
Adjust expansion valve for higher superheat .
Check crankcase heater .
Worn oil pump . Replace the oil pump .
Worn compressor bearings . Replace the compressor .
Loose fitting on oil line or pump housing gasket
leaking . (R22 only) Check and tighten system . Check bottom plate
or compressor .
Compressor short cycling . Check low pressure control setting .
Compressor
loses oil
Refrigerant leak .
Check system for leaks . Repair leaks and add
refrigerant .
Short cycling . Check low pressure control settings .
Refrigerant flood back .
Check thermal expansion valve setting . Check
for refrigerant overcharge .
Improper piping or traps . Verify proper piping slopes .
Running cycle is
too long or unit
operates
continuously
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 outdoor temperature .
Defective compressor . See “High suction pressure” .
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
defective thermostat .
Adjust or replace thermostat .
Always have a completed Pre-Start-Up Checklist, unit Start-Up Checklist, and Optional Accessories Checklist prior to requesting parts or
service information.