Lennox G32 SERIES Unit Information

Page 55
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 fail
ure.
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 installa
tion instructions for proper procedure.
ACTION 2 − Verify that the installed orifice size
match the size listed on the nameplate or installa
tion instructions.
ACTION 3 − Check gas valve sensing hose to in
sure no leaks are present.
ACTION 4 − Check the input rate to verify rate
matches value listed on nameplate.
ure.
G32−1 through −3 Units Only
LED#1−On
LED#2−Slow Flash
6.3.2
Gas orifices leak at the manifold con
nection.
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 meth
od for leak detection (see unit instructions).
LED#2
−
Sl
ow
Fl
as
h
G32−5 Units
LED#1−Slow Flash
LED#2−On
6.3.3
Air leakage at the connections be
tween the primary heat exchanger,
secondary heat exchanger, and com
bustion air blower.
ACTION 1 − Check for air leakage at all joints in
the heat exchanger assembly. Condition may
cause high CO2 with high CO.
ACTION 2 − Seal leakage if possible (high tem
perature silicon is recommended), replace heat
exchanger if necessary, tag and return heat ex
changer to proper Lennox personnel.
6.3.4
Insufficient flow through the heat ex
changer caused by a sooted or re
stricted heat exchanger.
ACTION 1 − Check for sooting deposits or other
restrictions in the heat exchanger assembly.
Clean assembly as outlined in instruction manu
al.
ACTION 2 − For G32V gas furnaces, check for
proper combustion and flow. CO2 should mea
sure between 7.9% and 8.5% for high fire and be
tween 5.5% and 6.3% for low fire. CO should
measure below .04% (400PPM) in an air−free
sample of flue gases.
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 openings. Cor
rect 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 Watchguard
flame failure.
6.4.1
Recirculation of flue gases. This con
dition causes rough ignitions and op
eration. Problem is characterized by
nuisance flame failures.
ACTION 1 − Check for proper flow of exhaust
gases away from intake vent. Remove any ob
stacles in front of the intake and exhaust vent
which would cause recirculation.
ACTION 2 − Check for correct intake and exhaust
vent installation.
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 re
place burners.

Lennox G32 SERIES Specifications

General

Brand	Lennox
Model	G32 SERIES
Category	Furnace
Language	English