46
■ 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
Comments to this Manuals