15. Check for gas leaks.
16. Replace main furnace door.
VI.
SERVICING HOT SURFACE IGNITER
The igniter does NOT require annual inspection. Check igniter
resistance before removal.
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
3. Disconnect igniter wire connection.
4. Check igniter resistance.
a. Using an ohm meter, check resistance across both igniter
leads in connector.
b. Cold reading should be between 45 ohms and 90 ohms.
c. If ohm reading is higher than 110 ohms, igniter is
cracked and must be replaced.
5. Remove igniter assembly.
CAUTION:
BURN HAZARD
Failure to follow this caution may result in minor
personal injury.
Allow igniter to cool before removal. Normal operating
temperatures exceed 2000°F.
a. Do not remove igniter from bracket while assembly is in
furnace. Using a 1/4 in. nutdriver, remove screw secur-
ing bracket and igniter assembly to bottom of burner
box. The screw in the bracket is always located toward
outside of burner box. The screw may be hidden by inlet
box or inlet pipe, but can be removed without removing
either. After removing screw, slide igniter and bracket
toward outside of burner box.
CAUTION:
UNIT DAMAGE HAZARD
Failure to follow this caution may result in premature
failure of the igniter.
The igniter is fragile. DO NOT allow it to hit the side of
the burner box opening while removing or replacing it.
b. Inspect igniter for a white area indicating a crack may be
present. If found, replace igniter.
NOTE:
A small crack cannot be seen on a new igniter. After a
period of operation, a white area will be visible around the crack.
c. If replacement is required, replace igniter on igniter
bracket external to furnace to avoid damage as the
silicon portion is very brittle and will easily crack or
shatter.
d. To remove igniter from igniter bracket, remove screw
holding igniter ceramic block to bracket and slowly
work ceramic block out of bracket.
6. To replace igniter/igniter assembly, reverse items 5a
through 5d.
7. Reconnect igniter wire connection.
8. Turn on gas and electrical supplies to furnace.
9. Verify igniter operation by initiating furnace control board
self-test feature or by cycling thermostat.
10. Replace main furnace door.
VII.
ELECTRICAL CONTROLS AND WIRING
WARNING:
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
There may be more than 1 electrical supply to the
furnace. Check accessories and cooling unit for additional
electrical supplies.
The electrical ground and polarity for 115-v wiring must be
maintained properly. Refer to Fig. 11 for field wiring information
and to Fig. 16 for furnace wiring information.
NOTE:
If the polarity is not correct, the STATUS LED on the
furnace control board will flash rapidly and prevent the furnace
from operating. The control system also requires an earth ground
for proper operation of the furnace control and flame sensor.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the control center. (See Fig. 12.) Any direct shorts of the 24-v
wiring during installation, service, or maintenance will cause this
fuse to blow. If fuse replacement is required, use ONLY a 3-amp
fuse of identical size. The control LED will flash status code 24
when fuse needs to be replaced.
Fig. 9—Burner Flame
A89020
;;
;;
BURNER FLAME
BURNER
MANIFOLD
Fig. 10—Gasket on Collector Box
A93081
RTV
PAM
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