34
■
Furnace not
operating.
■
Integrated
control module
LED display
provides “E6”
error code.
E6
■
Flame sense
microamp signal
is low.
■
Flame sensor is
coated/oxidized.
■
Flame sensor
incorrectly
positioned in
burner flame.
■
Lazy burner flame
due to improper
gas pressure or
combustion air.
■
Sand flame sensor if
coated/oxidized.
■
Inspect for proper
sensor alignment.
■
Check inlet air piping
for blockage, proper
length, elbows and
termination.
■
Compare current gas
pressure to rating plate
info. Adjust as needed.
■
Turn off power prior to
repair.
■
Sand flame sensor
with emery cloth.
■
See “Vent/Flue Pipe”
section for piping
details.
■
See rating plate for
proper gas pressure.
■
Furnace
operating on
low stage gas
with high stage
induced draft
blower
■
High stage
circulator
blower
(temperature, of
conditioned air,
lower than
typical).
■
Integrated
control module
LED display
provides “E7”
error code.
E7
■
Problem with
igniter circuit.
■
Improperly
connected igniter.
■
Shorted igniter.
■
Poor unit ground.
■
Igniter relay fault on
integrated control
module.
■
Check and correct
wiring from integrated
control module to
igniter
■
Replace shorted
igniter.
■
Check and correct
furnace ground wiring
■
Check igniter output
from control. Replace,
if necessary.
■
Turn off power prior to
repair.
■
Replace igniter with
correct replacement
part.
■
Replace control with
correct replacement
part.
■
Furnace fails to
operate on high
stage. Furnace
operates
normally on low
stage.
■
Integrated
control module
LED display
provides “E8”
error code.
E8
■
High-stage
pressure switch
circuit is closed
at start of
heating cycle.
■
Induced draft
blower is
operating.
■
Furnace is
operating on
low stage only.
■
High-stage
pressure switch
contacts sticking.
■
Shorts in pressure
switch circuit
wiring.
■
Replace high-stage
pressure switch.
■
Repair short in wiring.
■
Turn off power prior to
repair.
■
Replace pressure
switch with correct
replacement part.
■
Furnace fails to
operate on high
stage. Furnace
operates
normally on low
stage.
■
Integrated
control module
LED display
provides “E9”
error code.
E9
■
High-stage
pressure switch
circuit is not
closed.
■
Induced draft
blower is
operating.
■
Furnace is
operating on
low stage only.
■
Pressure switch
hose blocked,
pinched or
connected
improperly.
■
Blocked flue and/or
inlet air pipe,
blocked drain
system or weak
induced draft
blower.
■
Incorrect pressure
switch setpoint or
malfunctioning
switch contacts.
■
Loose or
improperly
connected wiring.
■
Inspect pressure
switch hose. Repair, 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.
■
Correct pressure
switch setpoint or
contact motion.
■
Tighten or correct
wiring connection.
■
Turn off power prior to
repair.
■
Replace pressure
switch with correct
replacement part.
■
Replace induced draft
blower with correct
replacement part.
Symptoms of
Abnormal
Operation
Diagnostic/
Staus LED
Code
Fault Description Possible Causes
Corrective Actions
Notes and Cautions
