18
26 Air Handler Troubleshooting Matrix
Symptoms of Abnormal Operation
Diagnostic /
Status LED
Codes
Fault Description
Possible Causes
Corrective Actions
No outdoor unit operations
Communication error with
outdoor unit
Improper low voltage wiring between
the indoor and outdoor unit
Outdoor control board lost power
duirng operation
Locate and correct improper low voltage wiring
issue
Identify reason outdoor control board lost power
during operation
No Air Handler operation
Open fuse
Short in low voltage wiring
Locate and correct short in low voltage wiring
Replace fuse with 3-amp automotive type
No Air Handler operation
Auxiliary switch (condensate
switch) open or open fuse
High water level in the evaporation coil
or short in low voltage wiring
Check evaporator drain pan, trap, piping
Replace fuse with 3-am automotive type
No Air Handler operation
Data not yet on network
No network data
Populate shared data set using memory card
No Air Handler operation
Invalid memory card data
Air Handler blower does not contain
an appropriate shared data set
Populate correct shared data using memory
card
Operation different than expected or no oper
Invalid memory card data
Shared data set on memory card has
been rejected by integrated control
module
Verify shared data set is correct for the specifc
model. Re-populate data using correct memory
card if required
No Air Handler operation
Circulator blower motor not
running with demand present
Loose or disconnected wiring
connection at circulator motor power
leads
Open circuit in inductor or loose
wiring connection at inductor (3/4 Hp
and 1 Hp models only)
Failed circulator blower motor
Tighten or correct wiring connection
Verify continuous circuit through inductor.
Replace if open or short circuit
Check circulator blower motor
No Air Handler operation
Integrated control module has
lost communications with
circulator blower motor
Loose wiring connection at circulator
motor control leads
Failed circulator blower motor
Failed integrated control module
Tighten or correct wiring connection
Check circulator blower motor, replace if
necessary
Check integrated control module, replace if
necessary
No Air Handler operation
Circulator blower motor horse
power in shared data set does
not match circulator blower
motor horse power
Incorrect circulator blower motor in Air
Handler
Incorrect shared data set in integrated
control module
Verify circulator blower if motor horse power is
the same specifed for the specifc Air Handler
model, replace if necessary
Verify shared data set is correct for the specifc
model, re-populate data using correct memory
card if required
Air Handler operates at reduced
performance
Airfow delivered is less than expected
Circulator blower motor is
operating in a power,
temperature, or speed limiting
condition
Blocked flters
Restrictive or undersized ductwork
High ambient temperatures
Check filters for blockage, clean flters or
remove obstruction
Check ductwork for blockage, remove
obstruction and verify all registers are fully open
Verify ductwork is appropriately sized for
system and resize/replace ass needed
