Bryant GAS-FIRED INDUCED-COMBUSTION FURNACES 373LAV Service And Maintenance Procedures Manual page 6

Fig. 9—Cleaning Heat Exchanger Cell
(8.) Reinstall cell inlet plates and burner assembly. Care
must be exercised to center burners in cell openings.
11. Clean flame sensor with fine steelwool.
12. Remove old sealant from center panel and collector box
flange and apply new sealant to collector box flange and
reinstall on center panel, making sure all 8 screws are
secure.
NOTE: A releasing agent such as PAM cooking spray or equiva-
lent (must not contain corn or canola oil, aromatic or halogenated
hydrocarbons or inadequate seal may occur) and RTV sealant
(G.E. 162, 6702, or Dow-Corning 738) are needed before starting
installation. DO NOT substitute any other type of RTV sealant.
G.E. 162 (P771-9003) is available through RCD in 3-oz. tubes.
13. Reinstall relief box and inducer assembly.
NOTE: If inducer assembly gasket is damaged, use RTV sealant
to seal inducer assembly to collector box.
NOTE: A releasing agent such as PAM cooking spray or equiva-
lent (must not contain corn or canola oil, aromatic or halogenated
hydrocarbons or inadequate seal may occur) and RTV sealant
(G.E. 162, 6702, or Dow-Corning 738) are needed before starting
installation. DO NOT substitute any other type of RTV sealant.
G.E. 162 (P771-9003) is available through RCD in 3-oz. tubes.
14. Reconnect wires to the following components.
a. Blocked vent safeguard switch.
b. Inducer motor.
c. Pressure switch.
d. Limit overtemperature switch(es).
e. Gas valve.
f. Hot surface igniter.
g. Flame-sensing electrode.
h. Flame rollout switch(es), if applicable.
15. Reinstall internal vent pipe and enclosure on downflow
furnaces only by reversing items 4a through 4c.
NOTE: A releasing agent such as PAM cooking spray or equiva-
lent (must not contain corn or canola oil, aromatic or halogenated
hydrocarbons or inadequate seal may occur) and RTV sealant
(G.E. 162, 6702, or Dow-Corning 738) are needed before starting
installation. DO NOT substitute any other type of RTV sealant.
G.E. 162 (P771-9003) is available through RCD in 3-oz. tubes.
16. Reinstall vent connector on furnace flue collar. After fully
assembling vent connector to furnace flue collar, securely
fasten vent connector to flue collar with 2 field-supplied,
corrosion-resistant, sheet metal screws located 180° apart
and midway up the collar.
17. Replace blower access door only.
18. Turn electrical power and gas to ON.
19. Set thermostat and check furnace for proper operation.
20. Verify blower airflow and speed changes between heating
and cooling.
21. Check for gas leaks.
WARNING: Never use a match or other open flame to
check for gas leaks. Use a soap-and-water solution. A
failure to follow this warning could result in fire, personal
injury, or death.
22. Replace control access door on upflow furnace.
23. On downflow/horizontal furnaces, remove blower access
A91252
door, replace control access door first, then replace blower
access door and secure with screws in front of door.
D. Electrical Controls and Wiring
CAUTION: There may be more than 1 electrical supply
to the unit. Check accessories and cooling unit for
additional electrical supplies.
The electrical ground and polarity for 115-v wiring must be
properly maintained. Refer to Fig. 10 for field wiring information
and to Fig. 12 for furnace wiring information.
NOTE: If the polarity is not correct, the STATUS LED on the
control center will flash rapidly and prevent the furnace from
heating. The control system also requires an earth ground for
proper operation of the control and flame sensing.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the control. (See Fig. 11.) Any shorts of the 24-v wiring during
installation, service, or maintenance will cause this fuse to blow. If
fuse replacement is required, use ONLY 3-amp fuses. The control
LED will display status code 24 when fuse needs to be replaced.
With power to the unit disconnected, check all electrical connec-
tions for tightness. Tighten all screws on electrical connections. If
any smoky or burned connections are found, disassemble the
connection, clean all parts, strip wire, and reassemble properly and
securely.
Reconnect electrical power to the unit and observe unit through 1
complete operating cycle. Electrical controls are difficult to check
without proper instrumentation; if there are any discrepancies in
the operating cycle, contact your dealer and request service.
The control in this furnace is equipped with an LED status light to
aid in installation, servicing, and troubleshooting. It can be viewed
through the sight glass or window on blower access door. The
control indicates status with the LED on continuously, rapid
flashing, or a code composed of 2 digits. (The first digit is the
number of short flashes, the second is the number of long flashes.)
For an explanation of status codes, refer to service label located on
blower access door or Fig. 13, and the troubleshooting guide.
The control stores 1 status code (the last status to occur) for a
period of 48 hrs or until the 115- or 24-v power is interrupted.
NOTE: Look into blower access door sight glass for current LED
status. Removing blower access door will open blower access door
switch and terminate 115-v power to control, and status code will
be erased.
1. To retrieve status code, proceed with the following:
NOTE: NO thermostat signal may be present at control center,
and all blower-OFF delays must be completed.
a. Leave 115-v power to furnace turned on.
b. Look into blower access door sight glass for current
LED status.
NOTE: Leave blower access panel installed to maintain power to
control to view current LED status.
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