50 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 ef
ciently, 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 cool-
ing. 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 com-
pletely; bypassing hot gas
Denergize solenoid coil, raise head pressure,
energize solenoid to break loose. If valve fails to
make complete shift, replace valve.
Cool with Heat Units
To Next Page
Loading...
Need help?
General
