Heating System Service Checks; Testing Gas Piping; Gas Valve Operation - Lennox G43UF SERIES Unit Information

Gas Valve Operation

Figure 14 shows possible gas valve used
1 − STOP! Read the safety information at the beginning of
this section.
2 − Set the thermostat to the lowest setting.
3 − Turn off all electrical power to the unit.
4 − This furnace is equipped with an ignition device which
automatically lights the burners. Do not try to light the
burners by hand.
5 − Remove the upper access panel.
6 − White Rodgers 36G Gas Valve − Switch gas valve le-
ver to OFF.
Honeywell VR8205 Gas Valve − Turn knob on gas
valve clockwise
Honeywell VR8205 with on / off switch − Move switch to
OFF.
7 − Wait five minutes to clear out any gas. If you then smell
gas, STOP! Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's instruc-
tions. If you do not smell gas go to next step.
8 − White Rodgers 36G Gas Valve − Switch gas valve lever
to ON.
Honeywell VR8205 Gas Valve − Turn knob on gas
valve counterclockwise
Honeywell VR8205 with on / off switch − Move switch to
ON.
9 − Replace the upper access panel.
10− Turn on all electrical power to to the unit.
11− Set the thermostat to desired setting.
NOTE − When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.
12− If the appliance will not operate, follow the instructions
Turning Off Gas to Unit" and call your service techni-
cian or gas supplier.
Turning Off Gas to Unit
1 − Set the thermostat to the lowest setting.
2 − Turn off all electrical power to the unit if service is to be
performed.
3 − Remove the upper access panel.
4 − White Rodgers 36G Gas Valve − Switch gas valve le-
ver to OFF.
Honeywell VR8205 Gas Valve − Turn knob on gas
valve clockwise
Honeywell VR8205 with on / off switch − Move switch to
OFF.
to OFF. Do not force.
to ON. Do not force.
to OFF. Do not force.
5 − Replace the upper access panel.
IV−HEATING SYSTEM SERVICE CHECKS
In case emergency shutdown is required, turn off
the main shut-off valve and disconnect the main
power to unit. These controls should be properly
labeled by the installer.
A−C.S.A. Certification
All units are C.S.A. design certified without modifications.
Refer to the G43UF Operation and Installation Instruction
Manual Information.
B−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. See table 15 if
gas pipe is suspect.
Compounds used on gas piping threaded joints should be
resistant to action of liquefied petroleum gases.
C−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 39.
GAS PIPING TEST PROCEDURE (Typical)
MANUAL SHUTOFF VALVE
CAP
GAS VALVE WILL NOT HOLD
TEST PRESSURE IN EXCESS
OF 0.5 PSIG (14"W.C.)
Page 33
IMPORTANT
FURNACE
ISOLATE
GAS VALVE
FIGURE 39