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11
PROBLEM POSSIBLE CAUSE TO CORRECT
Unit does not
run.
PROBLEM POSSIBLE CAUSE TO CORRECT
Dirty Filter.
Restricted air flow.
Inoperative thermostat.
Short of refrigerant.
Partially restricted capillary.
Inoperative fan motor.
Evaporator
coil freezes
up.
PROBLEM POSSIBLE CAUSE TO CORRECT
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.
Compressor
runs
continually.
Does not
cycle off.
PROBLEM POSSIBLE CAUSE TO CORRECT
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.
Loss of charge in thermostat bulb.
Loose or broken parts in
thermostat.
Incorrect wiring.
System switch open.
Thermostat
does not turn
unit on.
Excessive heat load.
Restriction in line.
Refrigerant leak.
Thermostat contacts stuck.
PROBLEM POSSIBLE CAUSE TO CORRECT
Turn to highest temperature setting to see of unit will cycle off.
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.
Thermostat set at coldest point
Thermostat contacts stuck.
Switch (On - Off) shorted.
Thermostat
does not
turn unit off.
Power disconnected.
System switch in “Off” position.
Branch circuit fuse blown or
circuit breaker tripped.
Inoperative system switch.
Loose or disconnected wiring at
switch.
Inoperative switch (On-Off).
Clean as recommended in Owner’s Manual.
Check for dirty or obstructed coil - clean as required.
Test for shorted thermostat or stuck contacts.
Deice coil and check for leak.
Deice coil. Check temperature differential across coil. Touch
test coil return bends for same temperature. Test for low
running current.
Test and replace if inoperative.
Check power source.
Set switch correctly.
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.
TROUBLESHOOTING