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2 − Turn off all electrical power to unit if service is to be per
formed.
3 − Remove access panel.
4 −
White Rodgers 36E gas valve
, switch lever to
OFF
. Do
not force.
5 − Replace access panel.
NOTE−On initial start−ups and when condensate trap is
dry, unit may turn itself off and on to allow condensate
trap to fill. This is normal operation.
C−Safety or Emergency Shutdown
Turn off unit power. Close manual and main gas valves.
D−Extended Period Shutdown
Turn off thermostat or set to UNOCCUPIED" mode. Close
all gas valves (both internal and external to unit) to guaran
tee no gas leak into combustion chamber. Turn off power to
unit. All access panels, covers and vent caps must be in
place and secured.
Refer to Maintenance" section of this manual for instruc
tions on how to prepare condensate assembly for ex
tended period shutdown.
IV−HEATING SYSTEM SERVICE CHECKS
A−A.G.A./C.G.A. Certification
All units are A.G.A. and C.G.A. design certified without
modifications. Refer to the G32 Operation and Installation
Instruction Manual Information.
B−Exhaust CO
2
and CO content
Carbon Dioxide is a colorless and odorless gas produced
in small amounts by all furnaces, including the G32, during
combustion process. See table 13 for CO
2
levels when the
unit is properly installed and operating normally. If unit ap
pears to be operating normally at or beyond the upper limit
of the CO
2
range, the unit should be checked for abnormal
ly high CO.
CO content will be less than 0.04% (400 PPM) in an air free
sample regardless of the firing rate used.
TABLE 13
G32 MODEL
HIGH HEAT NAT
LOW HEAT NAT
75,000
7.4%−8.8%
4.8%−6.4%
100,000
7.0%−9.0%
4.6%−6.6%
125,000
6.9%−8.7%
5.0%−6.5%
G32 MODEL
HIGH HEAT LP
LOW HEAT LP
75,000
7.5%−9.2%
5.5%−6.9%
100,000
8.0%−9.5%
5.2%−6.6%
125,000
7.9%−9.4%
5.3%−7.0%
Testing for abnormally high CO
2
and CO.
One method for testing the CO
2
/CO content is the Bachar
ach CO
2
test with the Fyrite CO
2
indicator. Other methods
of testing CO
2
/CO are available. Closely follow the instruc
tions included in the test kit you choose. Follow the proce
dure below in order to check CO
2
/CO on the G32 furnace.
1 − Drill size "R" or 11/32 in. on the exhaust vent, just exit
ing the cabinet and tap 1/8−27 NPT. This hole will be
used to draw your CO
2
/CO sample.
2 − Install a hose barb connector into test hole.
3 − Attach one end of Fyrite sampling tube to hose barb.
4 − Set thermostat to highest setting and allow unit to run
15 minutes.
5 − When CO
2
/CO testing is complete, turn off unit, re
move hose barb from exhaust vent and use a
1/8"
plastic plug to close off port.
C−Gas Piping
Gas supply piping should not allow more than 0.5"W.C. drop
in pressure between gas meter and unit. Supply gas pipe
must not be smaller than unit gas connection.
D−Testing Gas Piping
When pressure testing gas lines, the gas valve must be dis
connected and isolated. Gas valves can be damaged if
subjected to more than 0.5psig (14" W.C.). See figure 38
.
If
the pressure is equal to or less than 0.5psig (14"W.C.), use
the manual shut−off valve before pressure testing to isolate
furnace from gas supply.
FIGURE 38
GAS VALVE WILL NOT HOLD TEST PRESSURE IN
EXCESS OF 0.5 PSIG (14"W.C.)
MANUAL MAIN SHUT−OFF
VALVE WILL NOT HOLD
NORMAL TEST PRESSURE
CAP
FURNACE
ISOLATE
GAS VALVE
GAS PIPING TEST PROCEDURE (TYPICAL)
IMPORTANT
In case emergency shutdown is required, turn off
the main shutoff valve and disconnect the main
power to unit. These controls should be properly
labeled by the installer.
When checking piping connections for gas leaks, use pre
ferred means. Kitchen detergents can cause harmful corro
sion on various metals used in gas piping. Use of a specialty
Gas Leak Detector is strongly recommended. It is available
through Lennox under part number 31B2001.
Do not use matches, candles, flame or any other source of
ignition to check for gas leaks.