Lennox G23(X) User Manual

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PROBLEM 6: BURNERS LIGHT WITH HEATING DEMAND BUT UNIT SHUTS DOWN
PREMATURELY (CONT.)
Condition Possible Cause Corrective Action/Comments
6.3
- Combustion air blower energizes
with a heating demand.
- Burners light.
- Roll-out switch trips during the
heating demand.
- Diagnostic lights flash roll-out
failure.
6.3.1
Unit is firing above 100% of the
nameplate input.
ACTION 1 - Check that the manifold pressure
matches value listed on nameplate. See
installation instructions for proper proce-
dure.
ACTION 2 - Verify that the installed orifice
size match the size listed on the nameplate or
installation instructions.
ACTION 3 - Check gas valve sensing hose to
insure no leaks are present.
ACTION 4 - Check the input rate to verify rate
matches value listed on nameplate.
LED#1-On
LED#2-Slow Flash
6.3.2
Gas orifices leak at the manifold
connection.
ACTION 1 - Tighten orifice until leak is sealed.
NOTE: Be careful not to strip orifice threads.
ACTION 2 - Check for gas leakage at the
threaded orifice connection. Use approved
method for leak detection (see unit instruc-
tions).
6.3.3
Air leakage at the connections be-
tween the primary heat exchanger,
secondary heat exchanger, and
combustion air blower.
ACTION 1 - Check for air leakage at all joints
in the heat exchanger assembly. Condition
will cause high CO2 with high CO.
ACTION 2 - Seal leakage if possible, replace
heat exchanger if necessary, tag and return
heat exchanger to proper Lennox personnel.
6.3.4
Insufficient flow through the heat
exchanger caused by a sooted or
restricted heat exchanger.
ACTION 1 - Check for sooting deposits or oth-
er restrictions in the heat exchanger assem-
bly. Cleanassembly as outlined in instruction
manual.
ACTION 2 - Check for proper combustion.
CO2 should measure 6.5%-8.5%. CO should
measure below .04% (400PPM) in an air-free
sample of flue gases for either NG or LP.
6.3.5
Burners are not properly located in
the burner box.
ACTION 1 - Check that the burners are firing
into the center of the heat exchanger open-
ings. Correct the location of the burners if
necessary.
6.4
- Combustion air blower energizes
with a heating demand.
- Burners light roughly and the
unit fails to stay lit.
- Diagnostic lights flash watch-
g
uard flame failure.
6.4.1
Recirculation of flue gases. This
condition causes rough ignitions
and operation. Problem is charac-
terized by nuisance flame failures.
ACTION 1 - Check for proper flow of exhaust
gases away from intake vent. Remove any
obstacles in front of the intake and exhaust
vent which would cause recirculation.
ACTION 2 - Check for correct intake and ex-
haust vent installation. See instructions
guard flame failure
.
LED#1-Alternating Slow Flash
LED#2-Alternating Slow Flash
6.4.2
Improper burner cross-overs
ACTION 1 - Remove burner and inspect the
cross-overs for burrs, or any restriction or if
crossover is warped. Remove restriction or
replace burners.

Lennox G23(X) Specifications

General

Brand	Lennox
Model	G23(X)
Category	Furnace
Language	English