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8 -
NO
x
Units Only
-- Remove the screws holding the
flame baffles in the heat exchanger clam shells (See
figure 1). Carefully remove each baffle from each
heat exchanger section. To avoid damaging baffles,
turn baffles 90
before pulling out through heat ex
changer outlet.
IMPORTANT
Mark each baffle so that they are returned to the
proper heat exchanger section.
9 - Insert brush end of cable snake into top of one of the
heat exchanger openings. DO NOT FORCE CABLE
INTO HEAT EXCHANGER. Once the cable has
been inserted, operate drill on slow speed. Move the
cable in and out of the heat exchanger section three
or four arial or until sufficient cleaning is accom
plished. Reverse drill and slowly work cable out of
opening.
10 - Repeat this procedure for each heat exchanger
section.
11 - When the top heat exchanger sections are com
plete, place brush end of cable snake into the bot
tom openings of each of the heat exchanger sec
tions. Clean the bottom opening as described in
step 9.
12 - Remove cable from heat exchanger. Use a vacuum
to remove debris knocked loose during cleaning from
each heat exchanger section.
13 - Attach the exhaust end (positive pressure) of the
vacuum to the top of the heat exchanger sections.
Any loose debris will be forced to the bottom of the
heat exchanger section. Vacuum debris from bottom
openings.
14 - Replace collector box and combustion air blower.
Check gaskets for damage. Damaged seals must be
replaced to avoid heat exchanger leaks. Replace all
screws to the collector box and combustion air blower.
Leaving off screws may cause leaks.
15 - Replace upper vestibule panel, top cap, pressure
switch and ignition control.
16 - Clean burner by running a vacuum with a soft brush
attachment over face of burners. Visually inspect in
side of burners and crossovers for any blockage
caused by foreign matter. Remove any blockage.
17 -
NO
x
Units Only
-- Replace flame baffles in each heat
exchanger section. DO NOT BEND baffles. Baffles
should sit on the bottom of each heat exchanger
section.
18 - Replace burner / manifold assembly onto lower ves
tibule panel.
19 - Reconnect wires to ignition control, pressure switch,
roll-out switch, gas valve and combustion air blower.
Refer to wiring diagram in figure 22.
20 - Reconnect vent pipe to combustion blower outlet.
21 - Reconnect gas supply piping.
22 - Turn on power and gas supply to unit.
23 - Set thermostat and check furnace for proper operation.
24 - Check all piping connections, factory and field, for
gas leaks. Use a leak-detecting solution or other ap
propriate means.
CAUTION
Some soaps used for leak detection are corrosive
to certain metals. Carefully rinse piping thoroughly
after leak test has been completed. Do not use
matches, candles, flame, or other sources of igni
tion to check for gas leaks.
25 - If a leak is detected, shut gas and electricity off and
repair leak.
26 - Repeat steps 23 and 24 until no leaks are detected.
27 - Replace front access panel.