Troubleshooting - Friedrich HazardGard 60 Hz Service & Parts Manual

PROBLEM
UNIT DOES NOT RUN.
EVAPORATOR COIL
FREEZES UP.
COMPRESSOR RUNS
CONTINUALLY.
DOES NOT CYCLE OFF.
THERMOSTAT DOES
NOT TURN UNIT ON.
THERMOSTAT DOES
NOT TURN UNIT OFF.
8

TROUBLESHOOTING

POSSIBLE CAUSE
Power disconnected.
System switch in "Off" position. Set switch correctly.
Branch circuit fuse blown or
circuit breaker tripped.
Inoperative system switch.
Loose or disconnected wiring
at switch.
Inoperative switch (On-Off).
Dirty Filter.
Restricted air fl ow.
Inoperative thermostat.
Short of refrigerant.
Partially restricted capillary.
Inoperative fan motor.
Excessive heat load.
Restriction in line.
Refrigerant leak.
Thermostat contacts stuck.
Loss of charge in thermostat
bulb.
Loose or broken parts in
thermostat.
Incorrect wiring.
System switch open.
Thermostat set at coldest point Turn to highest temperature setting to see of unit will cycle off.
Thermostat contacts stuck.
Switch (On - Off) shorted.
TO CORRECT
Check power source.
Replace fuse, reset breaker. If repeats, check fuse or breaker
size. Check for shorts in unit wiring and components.
Test for continuity.
Check wiring and connections.
Connect per wiring diagram.
Test for continuity, 3 and 2, 5 and 6.
Clean as recommended in Owner's Manual.
Check for dirty or obstructed coil - clean as required.
Test for shorted thermostat or stuck contacts.
De-ice coil and check for leak.
De-ice coil. Check temperature differential across coil. Touch
test coil return bends for same temperature. Test for low
running current.
Test and replace if inoperative.
Test cooling performance of unit. Unit undersized.
Check for partially iced coil. Check temperature split across
coil.
Check for presence of oil on silver soldered connections.
Check for partially iced coil. Check split across coil. Check for
low running amperage.
Check operation of thermostat. Replace if contacts remain
closed.
Place jumper across thermostat terminals. If unit operates,
replace thermostat.
Check as above.
Connect per wiring diagram.
Test for continuity at switch terminals 2 and 3.
Disconnect power to the unit. Remove cover of thermostat
and check if contact is stuck, if so replace thermostat.
Test switch for open contacts at terminals 2 and 3 with switch
in "Off" position.