Lennox G23(X) User Manual

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PROBLEM 5: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER
ENERGIZES, IGNITOR IS ENERGIZED.
Condition Possible Cause Corrective Action/Comments
5.1
- Unit operates with a cooling and
continuous fan demand.
Combustion air blower energizes
5.1.1
Check that gas is being supplied to
the unit.
ACTION 1 - Check line pressure at the gas
valve. Pressure should not exceed 13 WC
for both natural and propane. Line pressure
should read a minimum 4.5 WC for natural
and 8.0WC for propane.
-
C
om
b
ust
i
on a
i
r
bl
ower energ
i
zes
with Heating demand.
- Ignitor is energized but unit fails
to light.
5.1.2
Miswiring of gas valve or loose
connections at multi-pin control
amp plugs or valve.
ACTION 1 - Check for correct wiring andloose
connections. Correct wiring and/or replace
any loose connections.
LED#1-Alternating Slow Flash
LED#2-Alternating Slow Flash
5.1.3
Defective gas valve or ignition
control.
ACTION 1 - Check that 24V is supplied to the
gas valve approximately 35 seconds after
heat demand is initiated.
ACTION 2 - Replace the valve if 24V is sup-
plied but valve does not open.
ACTION 3 - Replace the control board if 24V
is not supplied to valve.
PROBLEM 6: BURNERS LIGHT WITH A HEATING DEMAND BUT UNIT SHUTS DOWN
PREMATURELY
Condition Possible Cause Corrective Action/Comments
6.1
- Burners fire with a heating de-
mand.
Burners light but unit shuts off
6.1.1
Wrong concentric vent kit used for
terminating the unit.
ACTION 1 - Check vent termination kit
installed. 1-1/2 dia. concentric vent
(kit60 G77) for 50 and 75 inputs and 2 dia.
concentric vent (kit 33K97) for 100 &125 in-
puts.
-
B
urners
li
g
h
t
b
ut un
i
ts
h
uts o
ff
prior to satisfying T-stat demand.
- Diagnostic lights flash the pres-
sure switch code.
6.1.2
Condensate drain line is not drain-
ing properly.
ACTION 1 - Check condensate line for proper
vent slope, and any blockage. Condensate
should flow freely during operation of fur-
nace. Repair or replace any improperly
installed condensate lines.
LED#1-Off
LED#2-Slow Flash
6.1.3
Low pressure differential at the
pressure switch.
ACTION 1 - Check for restricted vent inlet or
exhaust. Remove all blockage.
ACTION 2: Check for proper vent sizing. See
installation instructions.
6.2
- Combustion air blower energizes
with a heating demand.
B li ht b t f il t t lit
6.2.1
Sensor or sense wire is improperly
installed.
ACTION 1 - Check that sensor is properly
located and that the sense wire is properly
attached to both the sensor and the control.
- Burners light but fail to stay lit.
-After 5tries the control diagnostics
flash the watchguard burners failed
to ignite code.
6.2.2
Sensor or sense wire is broken.
ACTION 1 - Check for a broken sensor.
ACTION 2 - Test continuity across the sense
wire. If wire or sensor are damaged replace
the component.
to ignite code.
LED#1-Alternating Slow Flash
LED#2-Alternating Slow Flash
6.2.3
Sensor or sensor wire is grounded
to the unit.
ACTION 1 - Check for resistance between
the sensor rod and the unit ground.
ACTION 2 - Check for resistance between
the sensor wire and the unit ground.
ACTION 3 - Correct any shorts found in cir-
cuit.
6.2.4
Control does not sense flame.
ACTION 1 - Check the microamp signal
from the burner flame. If the microamp sig-
nal is below 0.70 microamps, check the
sense rod for proper location or contamina-
tion.
ACTION 2 - Replace, clean, or relocate
flame sense rod. If rod is to be cleaned, use
steel wool or replace sensor. DO NOT
CLEAN ROD WITH SAND PAPER. SAND PA-
PER WILL CONTRIBUTE TO THE CONTAMI-
NATION PROBLEM. NOTE: Do not attempt
to bend sense rod.

Lennox G23(X) Specifications

General

Brand	Lennox
Model	G23(X)
Category	Furnace
Language	English