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Model ERCH-HP Energy Recovery Unit
Troubleshooting – 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.
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 and Unit Start-Up Checklist prior to requesting parts or service information.