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Specifications are subject to change without notice.
43
441 01 1422 00
NOTE
: If thermostat terminals are jumpered at the time blower
access door switch is closed, blower will run for 90 sec before
beginning a heating or cooling cycle.
c. Perform component self
−
test as shown at the bottom of
the
SERVICE label, located on the front of blower access
door.
d. Verify blower is rotating in the correct direction.
17. If furnace is operating properly, RELEASE BLOWER
ACCESS
DOOR SWITCH. Remove any jumpers or re-
connect
any disconnected thermostat leads. Replace blow-
er access
door.
18. Downflow or horizontal furnaces with vent pipe through
furnace only:
a. Install and connect short piece of vent pipe inside furnace
to existing vent.
b. Connect vent connector to vent elbow.
19. Reinstall outer door.
20. Cycle furnace through one complete
heating and cooling
cycle. Verify the furnace temperature rise
as shown in
“Adjustments” Section. Adjust temperature rise as
shown
in “Adjustments” Section. If outdoor temperature is
below
70
_
F, (21
_
C) turn off circuit breaker to outdoor unit be-
fore
running furnace in the cooling cycle. Turn outdoor
circuit
breaker on after completing cooling cycle.
CLEANING HEAT EXCHANGER
The following steps should be performed by a qualified
service agency:
NOTE
: If the heat exchangers get a heavy accumulation of soot
and carbon, they should be replaced rather than trying to clean
them thoroughly. A heavy build
−
up of soot and carbon indicates
that a problem exists which needs to be corrected, such as
improper adjustment of manifold pressure, insufficient or poor
quality combustion air, incorrect size or damaged manifold
orifice( s), improper gas, or a restricted heat exchanger. Action
must be taken to correct the problem.
If it becomes necessary to clean the heat exchangers because of
dust or corrosion, proceed as follows:
1. Turn OFF gas and electrical power to furnace.
2. Remove outer access door.
3. Disconnect vent connector from furnace vent elbow.
4. For downflow or horizontal furnace having an internal
vent pipe, remove internal vent pipe within the casing.
5. Disconnect wires to the following components. Mark
wires to aid in reconnection of (be careful when discon-
necting wires from switches because damage may occur):
a. Draft safeguard switch.
b. Inducer motor.
c. Pressure switch(es).
d. Limit over
−
temperature switch.
e. Gas valve.
f. Hot surface igniter.
g. Flame
−
sensing electrode.
h. Flame rollout switches.
6. Remove screws that fasten the collector box assembly to
the cell panel. Be careful not to damage the collector box.
Inducer assembly and elbow need not be removed from
collector box.
7. Disconnect gas line from gas manifold.
8. Remove the 5 screws that attach the burner assembly to
the cell panel. The gas valve and individual burners need
not be removed from support assembly. Remove NOx baf-
fles if installed.
NOTE
: Be very careful when removing burner assembly to
avoid breaking igniter. See Fig. 44 and 45 for correct igniter
location.
9. Using field
−
provided 25
−
caliber rifle cleaning brush,
36
−
in. (914 mm) long, 1/4” (6 mm) diameter steel spring
cable, a variable speed, reversible electric drill, and vacu-
um cleaner, clean cells as follows:
a. Remove metal screw fitting from wire brush to allow in-
sertion into cable.
b. Insert the twisted wire end of brush into end of spring ca-
ble, and crimp tight with crimping tool or crimp by strik-
ing with ball
−
peen hammer. TIGHTNESS IS VERY IM-
PORTANT.
9/32”
7.1mm
5/16”
7.9mm
A05025
Fig. 44
−
Igniter Position
−
Side View
1-7/8
47.6 mm
A05026
Fig. 45
−
Igniter Position
−
Top View
NOTE
: The materials needed in item 9 can usually be purchased
at local hardware stores.
(1.) Attach variable
−
speed, reversible drill to the end of
spring cable (end opposite brush).
(2.) Insert brush end of cable into the outlet opening of
cell
and slowly rotate with drill. DO NOT force ca-
ble.
Gradually insert cable into upper pass of cell.
(See Fig.
(3.) Work cable in and out of cell 3 or 4 times to obtain
sufficient cleaning. DO NOT pull cable with great
force. Reverse drill and gradually work cable out.
(4.) Insert brush end of cable in burner inlet opening of
cell, and proceed to clean 2 lower passes of cell in
same manner as upper pass.
(5.) Repeat foregoing procedures until each cell in fur-
nace
has been cleaned.