39
VersiVent Energy Recovery Ventilator
Symptom
Possible Cause
Corrective Action
Compressor
short cycles
Thermostat location or controls malfunction.
Check thermostat, check heat anticipator setting.
Improper refrigerant charge.
Check subcooling, verify superheat.
Defective low pressure control.
Check high or low pressure switch.
Poor air distribution.
Check ductwork for recirculating.
High discharge pressure.
See “high discharge pressure”.
Low airflow at evaporator(s).
Check blower operation and airstream restrictions.
Incorrect unit selection (oversized).
Contact factory.
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. Check crankcase heater operation.
Reheat flush cycle inadequate.
Contact factory.
Not enough
cooling or
lack of cooling
Refrigeration undercharged.
Check subcooling. Adjust charge, if necessary.
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.
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.
Liquid line
is frosted
or wet
Restriction in liquid line.
Clear restriction upstream of point of frosting.
Suction line is
frosting
Insufficient evaporator airflow.
Check airflow, check filters, check VFD control signal for proper
operation.
Malfunctioning or defective expansion valve. Check bulb of thermal expansion valve.
Frost on
evaporator
coil
Hot gas bypass valve not functioning
properly.
Check valve. If defective, replace.
Manual hot gas bypass valve closed.
Open valve.
Low load or airflow.
Increase airflow, check filters.
Always have a completed Pre-Start-Up Checklist and Start-Up Checklist prior to requesting parts or service
information.
Troubleshooting – Refrigeration Circuit
Troubleshooting - Energy Wheel
Symptom
Possible Cause
Corrective Action
Energy wheel
does NOT turn
Air seals are too tight.
Refer to Adjust the Air Seals found in the Start-Up
Components, Energy Wheel section.
Broken belt.
Replace.
No power to wheel motor.
Make sure wheel drive is plugged in. Verify power is
available.
Energy wheel
runs intermittently
Wheel motor overloads are tripping due to
rubbing between wheel and air seals.
Recheck air seals, make sure they are not too tight. Refer
to Adjust the Air Seals in the Start-Up Components,
Energy Wheel section.
