Planned Service - Lennox G71MPP Installation Instructions Manual

28 − Reinstall the combustion air inducer. Reconnect the
4−pin plug to the wire harness. Reconnect the two
wires to the backup secondary limit, if applicable.
29 − Reinstall pressure switches and reconnect pressure
switch wiring.
30 − Carefully connect combustion air pressure switch
hosing from pressure switches to proper stubs on
cold end header collector box.
31 − Reinstall condensate collars on each side of the fur-
nace. Reconnect drain tubing to collector box.
32 − Reinstall condensate trap on same side as exhaust
pipe. Reconnect condensate drain line to the conden-
sate trap.
33 − Use securing screws to reinstall flue collars to either
side of the furnace. Reconnect exhaust piping and ex-
haust drain tubing.
34 − Replace flexible exhaust tee on combustion air induc-
er and flue collars. Secure using three existing hose
clamps.
35 − Reinstall burner box assembly in vestibule area.
36 − Reconnect flame roll−out switch wires.
37 − Reconnect sensor wire and reconnect 2−pin plug from
ignitor.
38 − Secure burner box assembly to vestibule panel using
four existing screws. Make sure burners line up in
center of burner ports.
39 − Reinstall gas valve manifold assembly. Reconnect
gas supply line to gas valve.
40 − Reinstall burner box cover.
41 − Reconnect 2−pin plug to gas valve.
42 − Replace the blower compartment access panel.
43 − Refer to instruction on verifying gas and electrical con-
nections when re−establishing supplies.
44 − Follow lighting instructions to light and operate fur-
nace for 5 minutes to ensure that heat exchanger is
clean and dry and that furnace is operating properly.
45 − Replace heating compartment access panel.
Cleaning the Burner Assembly
1 − Turn off electrical and gas power supplies to furnace.
Remove upper and lower furnace access panels.
2 − Disconnect the 2−pin plug from the gas valve.
3 − Disconnect the gas supply line from the gas valve. Re-
move gas valve/manifold assembly.
4 − Mark and disconnect sensor wire from the sensor. Dis-
connect 2-pin plug from the ignitor at the burner box.
5 − Remove burner box cover and remove four screws
which secure burner box assembly to vest panel. Re-
move burner box from the unit.
NOTE − G71MPP−135 units are secured to the vesti-
bule panel by two additional screws. These screws
must be removed for servicing; however it is not nec-
essary to replace the screws.
6 − Use the soft brush attachment on a vacuum cleaner to
gently clean the face of the burners. Visually inspect
the inside of the burners and crossovers for any block-
age caused by foreign matter. Remove any blockage.
7 − Reconnect the sensor wire and reconnect the 2−pin
plug to the ignitor wiring harness.
8 − Reinstall the burner box assembly using the existing
four screws. Make sure that the burners line up in the
center of the burner ports.
9 − Reinstall the gas valve manifold assembly. Reconnect
the gas supply line to the gas valve. Reinstall the burn-
er box cover.
10 − Reconnect 2−pin plug to gas valve.
11 − Replace the blower compartment access panel.
12 − Refer to instruction on verifying gas and electrical con-
nections when re−establishing supplies.
13 − Follow lighting instructions to light and operate fur-
nace for 5 minutes to ensure that heat exchanger is
clean and dry and that furnace is operating properly.
14 − Replace heating compartment access panel.

Planned Service

A service technician should check the following items dur-
ing an annual inspection. Power to the unit must be shut off
for the service technician's safety.
Fresh air grilles and louvers (on the unit and in the room
where the furnace is installed) − Must be open and unob-
structed to provide combustion air.
Burners − Must be inspected for rust, dirt, or signs of water.
Vent pipe − Must be inspected for signs of water, cracked,
damaged or sagging pipe, or disconnected joints.
Unit appearance − Must be inspected for rust, dirt, signs
of water, burnt or damaged wires, or components.
Blower access door − Must be properly in place and pro-
vide a seal between the return air and the room where the
furnace is installed.
Return air duct − Must be properly attached and provide
an air seal to the unit.
Operating performance − Unit must be observed during
operation to monitor proper performance of the unit and the
vent system.
Combustion gases − Flue products must be analyzed and
compared to the unit specifications.
Problems detected during the inspection may make it nec-
essary to temporarily shut down the furnace until the items
can be repaired or replaced.
Instruct the homeowners to pay attention to their
furnace. Situations can arise between annual furnace in-
spections that may result in unsafe operation. For instance,
items innocently stored next to the furnace may obstruct
the combustion air supply. This could cause incomplete
combustion and the production of carbon monoxide gas.
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