Energy Wheel; Refrigeration Circuit - Greenheck ERCH-20 Installation, Operation And Maintenance Manual

Troubleshooting – Refrigeration Circuit
Symptom Possible Cause
Thermostat location or controls malfunction.
Improper refrigerant charge.
Defective low pressure control.
Compressor
Poor air distribution.
short cycles
High discharge pressure.
Low airflow at evaporator(s).
Incorrect unit selection (oversized).
Refrigerant leak.
Short cycling.
Compressor
loses oil
Refrigerant flood back.
Reheat flush cycle inadequate.
Refrigeration undercharged.
Dirty filter or evaporator coil.
Dirty or clogged condenser coil.
Not enough
cooling or Air or other non-condensables in system.
lack of cooling
Restriction in suction and liquid line.
Control contacts stuck.
Excessive load.
Liquid line
is frosted Restriction in liquid line.
or wet
Insufficient evaporator airflow.
Suction line is
frosting
Malfunctioning or defective expansion valve.
Hot gas bypass valve not functioning
properly.
Frost on
evaporator
Manual hot gas bypass valve closed.
coil
Low load or airflow.
Always have a completed Pre-Start-Up Checklist and Start-Up Checklist prior to requesting parts or service
information.
Troubleshooting - Energy Wheel
Symptom Possible Cause
Air seals are too tight.

Energy wheel

Broken belt.
does NOT turn
No power to wheel motor.
Energy wheel Wheel motor overloads are tripping due to
runs intermittently rubbing between wheel and air seals.
50 General Description - NOT model specific Energy Recovery Ventilator with Heating and Cooling
Corrective Action
Check thermostat, check heat anticipator setting.
Check subcooling, verify superheat.
Check high or low pressure switch.
Check ductwork for recirculating.
See "high discharge pressure".
Check blower operation and airstream restrictions.
Contact factory.
Check system for leaks. Repair leaks and add refrigerant.
Check low pressure control settings.
Check thermal expansion valve setting. Check for refrigerant
overcharge. Check crankcase heater operation.
Contact factory.
Check subcooling. Adjust charge, if necessary.
Check filter, coil and airflow.
Check coil and airflow.
Check equalized high side pressure with equivalent outdoor
temperature.
Check for restrictions in refrigerant circuit.
Check wiring.
Add more equipment or reduce room load.
Clear restriction upstream of point of frosting.
Check airflow, check filters, check VFD control signal for proper
operation.
Check bulb of thermal expansion valve.
Check valve. If defective, replace.
Open valve.
Increase airflow, check filters.
Corrective Action
See Air Seals in the Start-Up Components, Energy Wheel
section.
Replace.
Make sure wheel drive is plugged in. Verify power is
available.
Recheck air seals, make sure they are not too tight. See
Adjust the Air Seals in the Start-Up Components, Energy
Wheel section.
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