Greenheck ERCH - Energy Recovery Unit with Packaged DX (468151) - Manual (Page 47)

47
Energy Recovery Unit with Packaged DX
Troubleshooting - General Refrigeration Circuit
Symptom Possible Cause Corrective Action
Compressor noisy
or vibrating
Refrigerant overcharge . Check pressures and subcooling .
Liquid floodback .
Check thermal expansion valve setting . Check
for refrigerant overcharge .
Tubing rattle .
Dampen tubing vibration by taping or clamping .
Carefully bend tubing away from contact where
possible .
Scroll compressor rotating in reverse (3 phase) . Rewire for opposite rotation .
Worn or damaged compressor . Replace the compressor .
Improper mounting on unit base . Check that compressor is properly isolated .
High suction
pressure
Excessive load on evaporator coil .
Check for high entering wet bulb temperature .
Check for excessive air .
Compressor is unloaded .
Check head pressure, check thermal expansion
valve if not functioning properly, check pressure
drop across filter drier .
Expansion valve not secured to suction line .
Check the thermal expansion valve, ensure bulb
is insulated .
Check superheat . If superheat is high, then
valve is out of control and pegged wide open .
• Check bulb for contact.
• Adjust valve for superheat.
• Replace valve powerhead or valve.
Thermostatic expansion valve pressure limit
feature incorrect or inoperative . Overfeeding .
Check bulb location and clamping . Adjust
superheat . Replace expansion valve power
head .
Room load too large . Reduce the load or add more equipment .
Overcharged . Check pressures and subcooling .
High discharge
pressure
Thermal expansion valve setting .
Check thermal expansion setting and calibrate
superheat .
Air inlet to condenser dirty or obstructed .
Check for proper clearances and possible air
recirculating .
Condenser fan motor defective . Check condenser fan motor and capacitor .
Too much refrigerant . Remove excess refrigerant .
Non-condensable in system . Remove non-condensable from system .
Dirty condenser coil . Clean condenser coil .
Condenser fan not running or running
backwards . Check electrical circuit and fuse . Check fan
cycling controls .
Discharge service valve partially closed . Open valve .
High load conditions . Add more equipment or reduce load .
Always have a completed Pre-Start-Up Checklist, unit Start-Up Checklist, and Optional Accessories Checklist prior to requesting parts or
service information.