5-2
FOR SERVICE TECHNICIANS ONLY
Diagnostics and Troubleshooting (continued)
5-2
TROUBLESHOOTING CHART
1. Unit does not run.
1a. No power to unit.
1a. Check for power at receptacle,
good plug contact, fuses of
correct size and time delay
types. (Have customer contact
electrician if no power is avail-
able at receptacle.)
1b. Customer should contact a
qualified electrician to correct
this problem.
1c. Check all wiring and connec-
tions, thermostat, selector
switch, or control.
1b. Low voltage.
1c. Failed component or incorrect wiring.
PROBLEM
PROBABLE CAUSE
CORRECTION
2. Fan motor runs, com-
pressor does not run.
2a. Incorrect power supply voltage.
2b. Failed component or incorrect wiring.
2a. Check for proper voltage.
2b. Check all wiring connections,
overload, compressor, capaci-
tor, selector switch, or control.
3. Compressor runs, fan
motor does not run.
3a. Blower wheel or fan blade binding.
3b. Incorrect wiring.
3c. Motor windings shorted or motor shaft
stuck, open selector switch, defective
control.
3a. Check for proper clearance.
3b. Check all wiring.
3c. Check for open or shorted mo-
tor windings, open selector
switch, or control.
4. No cooling, compres-
sor and fan motor
running.
4a. Airflow restriction.
4a. Check for airflow through con-
denser and evaporator.
4b. Check sealed system for loss
of refrigerant or restrictions.
4b. Sealed system problem.
5. Insufficient cooling,
compressor and fan
motor running.
5a. Improper airflow.
5a. Clean or replace air filter.
Check for air passage restric-
tion or obstruction. Check for
dirty condenser, or evaporator.
5b. Check sealed system for loss
of refrigerant or restrictions.
5c. Advise customer that the unit
should be operating on a 60 Hz
electrical supply.
5d. Check power supply (see 1b).
5e. Insulating seals out of place or
missing on unit. Doors or win-
dows open.
5f. Excessive load. Advise cus-
tomer if load is excessive, or
installation is incorrect, or inad-
equate. Instruct on proper op-
eration of controls.
5g. Check for wrong motor, blower
wheel, or fan blade. Check for
binding of fan blade, blower
wheel, or motor shaft. Check
for low voltage and correct
capacitor.
5b. Sealed system problem.
5c. Operating 60 Hz unit on 50 Hz current.
5d. Low voltage.
5e. Improper seals.
5f. Improper use/size for area to be cooled.
5g. Fan speed too slow.
