Electrical Controls And Wiring - Bryant 312AAV L Series Service And Maintenance Procedures Manual

Fig. 4—Position of Igniter to Burner
Fig. 5—Cleaning Heat Exchanger Cell
(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 2 upper passes.
(5.) Repeat foregoing procedures until each cell in
furnace has been cleaned.
(6.) Using vacuum cleaner, remove residue from each
cell.
(7.) Using vacuum cleaner with soft brush attachment,
clean burner assembly.
(8.) Clean flame sensor with fine steel wool.
(9.) Reinstall burner assembly. Center burners in cell
openings.
9. Remove old sealant from cell panel and inducer backing
plate flange and apply new sealant to flange and reinstall on
cell panel, making sure all 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.
10. Reinstall elbow and inducer assembly.
11. Reconnect wires to the following components (Use connec-
tion diagram on wiring label, if wires were not marked for
reconnection locations.):
a. Draft safeguard switch.
b. Inducer motor.
c. Pressure switches.
d. Limit overtemperature switch.
e. Gas valve.
f. Hot surface igniter.
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g. Flame-sensing electrode.
h. Flame rollout switches.
12. Reinstall internal vent pipe, if applicable.
13. Reinstall vent connector on furnace vent elbow. Securely
fasten vent connector to vent elbow with 2 field-supplied,
corrosion-resistant, sheet metal screws located 180° apart.
14. Replace blower access door only.
15. Set thermostat above room temperature and check furnace
for proper operation.
16. Verify blower airflow and speed changes between heating
and cooling.
17. Check for gas leaks.
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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.
18. Replace outer access door.
IV. 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
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properly maintained. Refer to Fig. 6 for field wiring information
and to Fig. 7 for furnace wiring information.
NOTE: If the polarity is not correct, the STATUS LED on the
control 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 electrode.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the control. (See Fig. 8.) 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 a 3-amp fuse. 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, and wire conductors, 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.
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