Greenheck ERCH - Energy Recovery Unit with Packaged DX (468151) - Manual (Page 45)

45
Energy Recovery Unit with Packaged DX
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 400 psi and will not reset
above 250 psi for R22 or 600/420 respectively
for R410a) .
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 25 psig for R22,
50 psig for R410a
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 .
Troubleshooting – General Refrigeration Circuit
IMPORTANT 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 a qualified HVAC Technician .
NOTE: Unit is equipped with a phase loss/phase reversal control . If system does not start, check phase of electrical supply .
Always have a completed Pre-Start-Up Checklist, unit Start-Up Checklist, and Optional Accessories Checklist prior to requesting parts or
service information.