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A−Filters
At the beginning of each heating season, the system
should be checked as follows:
1 − Filters should be inspected monthly and must be
cleaned or replaced when dirty to ensure proper fur
nace operation.
2 − Reusable foam filters used with the G32 can be
washed with water and mild detergent. When dry, they
should be sprayed with filter handicoater prior to rein
stallation. Filter handicoater is RP Products coating no.
418 and is available as Lennox part no. P85069.
3 − If replacement is necessary, order Lennox part no.
31J81 for 14" x 25" (356 x 635mm) filter for G32Q3−75
units and P87831 for 20" x 25" (508 x 635mm) filter for
G32−100 and 125 units.
B−Cleaning Heat Exchanger and Burners
NOTE − Surgical mask and safety glasses should be
worn when cleaning heat exchanger and burners.
If cleaning the heat exchanger becomes necessary, follow
the below procedures and refer to figure 1 when disassem
bling unit. Use papers or protective covering in front of fur
nace while removing heat exchanger assembly.
1 − Turn off electrical and gas power supplies to furnace.
2 − Remove upper and lower furnace access panels.
3 − Remove four (4) screws around air intake fitting and lift
intake pipe up and away.
4 − Loosen hose clamp securing top of flue transition to
bottom of flue collar. Remove screw securing flue col
lar to top cap and lift exhaust pipe and flue collar up
and away.
5 − If electrical field makeup box is located inside the unit,
it must be removed.
6 − Remove gas supply line connected to gas valve.
7 − Mark all gas valve wires and disconnect them from
valve. Mark and remove wires from flame rollout
switch.
8 − Remove top cap of unit.
9 − Remove sensor wire from SureLight control. Discon
nect 2pin plug from the ignitor.
10− Mark and disconnect pressure switch tubing from both
sides of the pressure switch.
11− Loosen two (2) screws holding gas manifold support at
vestibule panel.
12− Remove four (4) burner box screws at the vestibule
panel and remove burner box and gas valve/manifold
assembly with bracket.
13− Drain condensate trap. Disconnect condensate line
from the outside of unit. Remove condensate line from
condensate trap by turning the adapter fitting counter
clockwise. The fitting has standard right hand threads.
14− Disconnect the drain hose from the flue transition to
the elbow on the cold header (collector) box trap.
15− Disconnect the 3pin plug from the combustion air
blower at the blower deck. Remove four (4) screws
from combustion air blower and remove flue transition
and blower assembly from cabinet. Take care not to
lose the combustion air orifice.
16− Disconnect 9pin plug from the blower compartment at
the blower deck.
17− Remove 9pin plug above the blower deck.
18− Remove the limit switch and the pressure switch from
the vestibule panel.
19− Remove two (2) screws from the front cabinet flange at
the blower deck. Remove front screws from cabinet at
blower deck on left and right sides. Cabinet sides must
be slightly spread to clear heat exchanger passage.
20− Remove screws along vestibule sides and bottom
which secure vestibule panel and heat exchanger as
sembly to cabinet. Remove heat exchanger then re
move cold end header box.
21− Back wash heat exchanger with soapy water solution
or steam.
If steam is used it must be below 275
F
(135
C) .
22− Thoroughly rinse and drain the heat exchanger. Soap
solution can be corrosive so take care that entire as
sembly is completely rinsed.
23− Re−install heat exchanger into cabinet making sure
that the clamshells of the heat exchanger assembly
are resting in the notches of the support located at the
rear of the cabinet. This can be viewed by removing
the indoor blower and examining through the blower
opening.
24− Resecure the supporting screws along the vestibule
sides and bottom to the cabinet.
25− Reinstall cabinet screws on sides and front flange at
blower deck.
26− Reinstall the limit switch and pressure switch (−75 unit
will have a second switch) on the vestibule panel.
27− Reinstall 9pin plug to blower deck and connect it to
the 9pin plug from below the blower deck.
28− Reinstall the combustion air blower. Be careful that
the plastic orifice on the blower inlet has not fallen out.
See figure 1. Reconnect the 3pin plug to the wire har
ness. Reinstall the flue transition in the cabinet and
reattach the drain tube. Route the drain tube below
the combustion air blower housing and to the elbow on
the cold header (collector) box trap. See figure 18.
29− Reinstall condensate line with adapter to condensate
trap. Use fresh Teflon tape to ensure a leak−free joint.
Reconnect to condensate line outside of the unit.