Specifications

21
ModPac II, 9/09-15
PROBLEM/SYMPTOM LIKELY CAUSE(S) CORRECTION
A. Unit does not run. 1. Power supply problem.
2. Blown fuse or breaker.
3. Shut off by external thermostat or
thermostat is defective.
4. Internal component or connection failure.
1. Check power supply for adequate phase and voltage.
Check wiring to unit and external breakers or fuses.
2. Check circuit protection devices for continuity.
3. Check operation of wall-mounted thermostat.
4. Check for loose wiring. Check components for failure
B. Unit runs for long pe
-
riods or continuously;
cooling is insufcient.
1. Unit undersized for job.
2. Loss of refrigerant.
3. Component failure.
4. Dirty lter or reduced airow.
1. Add additional units for greater capacity.
2. Check for proper charge and possible leak.
3. Check internal components, especially compressor
for proper operation.
4. Check air lter(s). Check blower operation. Remove
airow restriction.
C. Unit cycles on
Compressor Overload
1. Loss or restriction of airow.
2. Restriction in refrigerant circuit.
3. Refrigerant overcharge (following eld
service)
1. Check blower assembly for proper operation. Look
for airow restrictions, e.g., the air lter. Check blower
motor and condenser fan.
2. Check for blockage or restriction, especially lter drier
and capillary tube assembly.
3. Evacuate and recharge to factory specications.
D. Unit blows fuses or
trips circuit breaker.
1. Inadequate circuit ampacity.
2. Short, loose, or improper connection in
eld wiring.
3. Internal short circuit. Loose or improper
connection(s) in unit.
4. Excessively high or low supply voltage
or phase loss (3ø only).
1. Note electrical requirements in Chapter 2 and correct
as necessary.
2. Check eld wiring for errors.
3. Check wiring in unit. See wiring and schematic dia-
grams. Test components (especially the compressor)
for shorts.
4. Note voltage range limitations specic to the com-
pressor troubleshooting section.
E. Water on oor near
unit or leaking from
cabinet.
1. Obstruction in condensate line.
2. Obstruction or leak in condensate pan.
3. Unit is not level.
1. Check for clog or restriction.
2. Check pan for leak or blockage.
3. Level unit.
F. No space heating
or reduced heating
(units equipped with
resistance elements)
1. Defective heating element(s).
2. Thermal limit open.
3. Defective heater contactor.
1. Check resistance element(s) for continuity.
2. Check continuity across thermal limit switch.
3. Check for proper operation.
4.2 Failure Symptoms Guide