Sears Furnace Manual: Troubleshooting for Common Models

Heating Request with Gas Shut Off:

24 VAC signal applied to W terminal of FCB.

The FCB will attempt 4 cycles for ignition then go to soft lockout for 3 hours then try for ignition again as long as the heat call remains. Power reset will clear lockout.

•Inducer motor turns on

•Following a 15 second prepurge delay, the igniter begins warm up.

•The igniter glows red-hot for 22 seconds, then turns off. The FCB flashes error code 6.

•The igniter stays off for 17 seconds, then begins to warm up again.

•The igniter glows red hot for 22 seconds then turns off. The FCB continues flashing error code 6.

•The igniter stays off for 17 seconds, then begins to warm up again.

•The igniter glows red hot for 22 seconds then turns off. The FCB continues flashing error code 6.

•The igniter stays off for 17 seconds, then begins to warm up again.

•The igniter glows red hot for 22 seconds then turns off. The FCB proceeds to soft lockout and stops flashing error code 6 and begins flashing error code 6 + 1.

•The inducer motor de-energizes after a 15 second post purge.

Control Board Diagnostic Codes (See Figure 40)

OFF

= 24VAC

or 115VAC

is off,

fuse is open

Heartbeat

=

Normal

operation

or no

previous

Diagnostic

Code

ON SOLID

=

Soft

Lockout

-

Furnace

Control

Error

(1 hr delay)

If code

repeats immediately

following power reset then replace control

1

Flash

= Not

used

2

Flashes

=

Pressure

switch(es)

closed

when

should

be

open

3

Flashes

= Pressure

switch

open

when

should

be

closed

4

Flashes

=

Limit

or

roll-out

switch

open

(less

than

2 minutes)

5

Flashes

= Flame sensed

out

of

sequence

6

Flashes

=

Failure

to ignite

or

flame

sense

lost

while

running

6

+ 1 Flashes

=

Soft

Lockout

-

Max

trials

for

ignition

reached

(3hr delay)

7

Flashes

=

Soft

Lockout

-

Limit

or

roll-out

switch

open longer

than 2 minutes (1

hr

delay)

(roll-out switch requires manual reset)

8

Flashes

=

Permanent

Lockout

-

Gas valve

relay

contact

stuck

closed

or miswired

gas valve (power reset only)

10

Flashes

=

Line

voltage

(115VAC)

polarity

reversed.

If twinned,

refer

to twinning

kit

instructions

*If status code recall is needed, briefly (2-3 seconds) remove then reconnect one limit switch wire (main or rollout) to display last stored

status code. Do not remove power or blower door before initiating status code recall or code will be lost. Code is automatically cleared after 72 hours or upon power reset.

*Proper flame sense microamps: 0.7 microamps D.C. minimum 2.0 - 4.0 microamps nominal

Control Board

441 01 261302