29
Symptom
Possible cause
Corrective action
Unit not operating
No power to unit.
Apply proper power to unit.
Incorrect power to unit.
Apply correct power to unit and check for damaged components and/or blown
fuses, if furnished.
Power distribution panel switch
or circuit breaker in “OFF”
position.
Turn power distribution panels switch or circuit breaker to “ON” position.
Unit toggle disconnect switch
in “OFF” position.
Turn unit toggle disconnect switch to “ON” position.
Fan switch or thermostat
system switch in “OFF”
position.
Turn fan switch or thermostat system switch to “ON” position.
Blown or defective unit main
fuse, if furnished.
Check for possible defective component or improper wiring and replace fuse.
Defective toggle, fan or
thermostat
system switch.
Momentarily jumper suspected component to simulate closed contacts and
achieve unit operation. Replace defective device with known good part.
Loose or improper wiring
from power distribution and/
or remote mounted control
devices.
Verify all wiring connections and terminations, and verify proper wiring of all
incoming power devices and remote mounted controls.
Level switch activated, drain
pan clogged
Remove debris from drain pan, unclog pan, unclog drain and emtpy.
Unit blows fuse
when power is
applied to unit
Defective or improperly wired
component.
Using a battery powered continuity tester, check for shorted or grounded
components starting at incoming power. Note position of all controls during
various component checks. Caution: some voltages have isolated common
which may not show a short to chassis ground. Be sure to isolate each control
to eliminate faulty reading through a parallel wired component.
Fan doesn’t
operate
Thermostat system switch in
“OFF” position.
Turn thermostat system switch to “ON” position.
Remote “start/stop” switch in
“OFF” position.
Turn remote “start/stop” switch to “ON” position.
Loose or improper wiring from
fan switch or thermostat to
unit.
Verify all wiring connections and terminations, and verify proper wiring of all
control devices.
Loose or improper wiring from
remote “start/stop” switch to
unit “start/stop” relay.
Verify all wiring connections and terminations, and verify proper wiring of
remote “start/stop” switch.
Defective “start/stop” relay.
Momentarily jumper “start/stop” relay to simulate proper relay operation.
Replace defective “start/stop” relay.
Defective fan motor.
Verify proper fan switch operation and replace defective fan motor.
Troubleshooting
Troubleshooting
