Bryant GAS-FIRED INDUCED-COMBUSTION FURNACE 393AAV User Manual

Page 5

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.

19. Replace control access door.

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. 5 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. 6.) 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, 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 the 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 short flashes, the second is the number of longs flashes.)
For an explanation of status codes, refer to service label located on
blower access door or Fig. 8, and the troubleshooting guide.
The control stores 1 status code (the last status code to occur) for
a period of 48 hr or until the 115- or 24-v power is interrupted.

NOTE:

Look into blower access door sight glass for current LED

status BEFORE removing the blower access door. 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 shall be present at control, 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.

c. Remove control access door.

d. BRIEFLY remove either wire from the main limit switch

until LED goes out, then reconnect it.

NOTE:

If wire to main limit is disconnected longer than 4 sec,

main blower starts, and retrieval request is ignored.

2. When above items have been completed, the following will

occur:

a. LED flashes a status code 4 times. Record this status

code for further troubleshooting.

b. Inducer motor starts and continues to run the entire

component test.

c. Hot surface igniter is energized for 15 sec, then de-

energized.

d. Main blower operates at heating speed for 10 sec, then

turns off.

e. Main blower operates at cooling speed for 10 sec, then

turns off.

f. Inducer motor stops.

Items a through e above will assist in furnace troubleshoot-
ing since all components are functionally operated except
the gas valve. This procedure is also referred to as "Com-
ponent Test."

3. Operate furnace through 1 heat cycle to test for proper

operation and check LED status.

4. If furnace is operating properly and LED indicates proper

operation, replace control access door.

5. Component Test can also be initiated by performing the

following:

a. Remove control access door.

b. Remove blower access door.

c. Manually close blower access door switch.

WARNING:

Blower access door switch opens 115-v

power to control. No component operation can occur.
Caution must be taken when manually closing this switch
for service purposes. Failure to follow this warning could
result in personal injury or death.

d. BRIEFLY short (jumper) TEST, 3/16-in. quick-connect

terminal on control (adjacent to LED status light), and
C

-24V terminal on furnace control thermostat termi-

nal block. (See Fig. 6.)

NOTE:

If TEST to C

-24V terminals are jumpered longer than

2 sec, LED will flash rapidly, and test request will be ignored.

e. Component Test will function as described in item 2

above.

f. Check LED status.

Fig. 4—Position of Igniter to Burner

A99286

BURNER

IGNITER

11 32

7 8

IGNITER
ASSEMBLY

CELL
PANEL

BURNER

13 32

HOT
SURFACE
IGNITER
ASSEMBLY

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