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Cool with Heat Units
COMPLAINT
Room temperature uneven
(Heating cycle)
Does not heat adequately
Unit cools when heat is called
for
Cooling adequate, but heating
insufficient
45
TROUBLESHOOTING
CAUSE
Bad indoor ambient thermistor
Fan speed too low
Exhaust or fresh air door open
Dirty filter
Unit undersized
Heater hi-limit control cycling on & off
Shorted or open supplementary heater
Incorrect wiring
Incorrect wiring
Defective solenoid coil
Reversing valve fails to shift
Reversing valve failing to shift com-
pletely; bypassing hot gas
Figure 716 (Troubleshooting Tips)
SOLUTION
Check diagnostic codes. Check Thermistors.
Replace as needed.
Set at higher fan speed.
Check if operating properly. Instruct customer
on proper use of control
Clean (See Routine Maintenance)
Check heat rise across coil. If unit operates effi
ciently, check if insulation can be added to attic
or walls. If insulation is adequate, recommend
additional unit or larger one
Check for adequate fan air across heater. Check
for open hi-limit control.
Do ohmmeter check.
Check applicable wiring diagram
Refer to applicable wiring diagram
Check for continuity of coil
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.
Denergize solenoid coil, raise head pressure,
energize solenoid to break loose. If valve fails to
make complete shift, replace valve.
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Table of Contents
Troubleshooting
