Greenheck Fan Energy Recovery Ventilator with Heat Pump 473501 - Manual (Page 31)

31 Model ERCH-HP Energy Recovery Unit
Symptom Possible Cause Corrective Action
Compressor
will not run
or
does not
try to start
Open disconnect switch or circuit breaker. Close switch and / or breaker.
Compressor contactor not closing.
Check voltage to contactor coil, transformer, slave
relay, system. Replace parts as necessary.
Blown fuse or tripped breaker.
Check for reason and repair. Replace fuse after
correcting problem.
Low line voltage.
Check line voltage. If more than 10% from
compressor marking, correcting is necessary.
Compressor motor protector open.
Motor thermal protector automatically resets.
Allow time (2 hrs.) for compressor to cool down so
protector will reset. Restart and check for reason
overheat occurred.
Compressor defective.
Check motor for open circuit, short circuit,
grounded windings or burn out.
Compressor may be seized; check refrigerant.
If necessary, replace compressor.
High or low pressure switch open or defective.
If manual reset (high pressure), reset switch.
(Switch opens at 600 psi and will not reset above
420 psi for R-410A.
If auto reset (low pressure) does not reset and
everything else is OK, replace switch.
Open room thermostat or control
(no cooling required). Check room temperature. If temperature is proper,
wait for thermostat to close.
Loose wiring. Check all wire terminals and tighten as necessary.
Compressor starts
but cuts out on low
pressure
Low pressure
switch activates
at 50 PSIG for R-410A
Low refrigerant charge. Check refrigerant pressures.
Airflow restricted.
Check for dirty evaporator coil, dirty filters,
dampers closed, iced evaporator coil, improper
belt, check motor amps, check duct design.
Restriction in refrigerant line.
Check refrigerant pressure, check and adjust
thermal expansion valve. If not functioning properly,
check for pressure drop across the filter drier.
Defective low pressure switch. Replace.
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.
NOTE: Unit is equipped with a phase loss/phase reversal control. If system does not start, check phase of electrical supply.
Troubleshooting – Refrigeration Circuit
TROUBLESHOOTING NOTE
Before any components are changed on the
refrigeration system, the cause of the failure must be
identified. Further problems will exist unless the true
cause or problem is identified and corrected.
IMPORTANT
Do not release refrigerant to the atmosphere! If
required service procedures include the adding or
removing of refrigerant, the service technician must
comply with all federal, state and local laws. The
procedures discussed in this manual should only be
performed by an EPA Certified Technician.