Install Instructions

47
T ROUBLESHOOTING C HART
Symptom LED Status Fault Description Corrective Actions
Induced draft blower and circulator
blower runs continuously
No furnace operation

Flame sensed with no call for heat
Short to ground in flame sense circuit
Lingering burner flame
Slow closing gas valve
Correct short at flame sensor or in flame sensor wiring
Check for lingering or lazy flame
Verify proper operation of gas valve
No furnace operation

Open fuse
Short in low voltage wiring
Replace fuse
Locate and correct short in low voltage wiring
Normal furnace operation

Flame sense micro amp signal is low
Flame sensor is coated/oxidized
Flame sensor incorrectly positioned in
burner fame
Lazy burner flame due to improper gas
pressure or combustion air
Clean flame sensor if coated or oxidized
Inspect for proper flame sensor alignment
Check inlet air piping for blockage, proper length, elbows,
and termination
Compare current gas pressure to rating plate and adjust as
needed
Furnace f ails to operate

Problem with igniter circuit
Improperly connected or shorted
igniter
Poor unit ground
Igniter relay fault on integrated control
module
Check and correct wiring from integrated control module to
igniter
Diagnose and replace shorted igniter as needed
Verify and correct unit ground wiring if needed
Check igniter output from control, replace if necessary
Furnace f ails to operate on high
stage; f urnace operates normally
on low stage
Induced draft blower operating

High stage pressure switch circuit is
closed at start of heating cycle.
High stage pressure switch contacts
sticking
Shorts in pressure switch circuit wiring
Diagnose and replace high stage pressure switch if needed
Repair short in wiring
Furnace f ails to operate on high
stage; f urnace operates normally
on low stage
Induced draft blower operating

High stage pressure switch circuit is
not closed
Furnace is operating on low stage only
Inspect pressure switch hose, repair/replace if necessary
Inspect flue and/or inlet air piping for blockage, proper
length, elbows, and termination
Check drain system, correct as necessary
Check induced draft blower performance, correct as
necessary
Tighten or correct wiring connection
Furnace f ails to operate

Polarity of 115 volt AC is reversed
Poor unit ground
Correct polarity, check and correct wiring if necessary
Verify proper ground, correct if necessary
Furnace f ails to operate

Gas valve is not energized when it
should be
External Gas Valve Error
Check wiring in gas valve circuit
Replace integrated control board
Furnace f ails to operate

Gas valve is energized when it should
not be
Internal gas valve error
Check wiring in gas valve circuit
Replace integrated control board