59 PB
TROUBLESHOOTING
COMPLAINT CAUSE SOLUTION
Room temperature uneven
(Heating cycle)
Bad indoor ambient thermistor
Check diagnostic codes. Check Thermistors. Replace as
needed.
Fan speed too low Set at higher fan speed.
Does not heat adequately
Exhaust or fresh air door open
Check if operating properly. Instruct customer on proper use
of control
Dirty lter Clean (See Routine Maintenance)
Unit undersized
Check heat rise across coil. If unit operates efciently, check
if insulation can be added to attic or walls. If insulation is
adequate, recommend additional unit or larger one
Heater hi-limit control cycling on & off
Check for adequate fan air across heater. Check for open hi-
limit control.
Shorted or open supplementary heater Do ohmmeter check.
Incorrect wiring Check applicable wiring diagram
Unit cools when heat is called
for
Incorrect wiring Refer to applicable wiring diagram
Defective solenoid coil Check for continuity of coil
Reversing valve fails to shift
Block condenser coil & switch unit to cooling. Allow pressure
to build up in system, then switch to heating. If valve fails to
shift, replace valve.
Cooling adequate, but heating
insufcient.
Reversing valve failing to shift
completely; bypassing hot gas
De-energize solenoid coil, raise head pressure, energize
solenoid to break loose. If valve fails to make complete shift,
replace valve.
Cool with Heat Units
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