3DJH
PROBLEM 6: BURNERS LIGHT WITH HEATING DEMAND BUT UNIT SHUTS DOWN
PREMATURELY (CONT.)
6.5
- Combustion air blower energizes
with a heating demand.
- Burners light.
- Diagnostic lights flash watch
guard flame failure.
- NOTE Unit might go into 60
minute Watchguard mode depend-
ing on intermittent nature of sen-
sor signal.
LED#1-Alternating Slow Flash
LED#2-Alternating Slow Flash
6.5.1
Loose sensor wire connection
causes intermittent loss of flame
signal.
ACTION 1 - Check that the sensor is properly
located.
ACTION 2 - Check that the sense wire is prop-
erly attached to both the sensor and the con-
trol. Pay extra attention to the pin connectors.
PROBLEM 7: CONTROL SIGNALS LOW FLAME SENSE DURING HEATING MODE
Condition
Possible Cause
Corrective Action/Comments
7.0
- Unit operates correctly but the
diagnostic lights flash low flame
sense code
7.1.1
Sense rod is improperly located on
the burner.
ACTION 1 - Check the sense rod for proper
location on the burner. Properly locate the
sense rod or replace if rod cannot be located
correctly.
sense code.
LED#1-Slow Flash
LED#2-Fast Flash
7.1.2
Sense rod is contaminated.
ACTION 1 - Check sense rod for contamina-
tion or coated surface. Clean the sense rod
with steel wool or replace sensor. DO NOT
USE SAND PAPER TO CLEAN ROD. SAND
PAPER WILL CONTRIBUTE TO THE CON-
TAMINATION PROBLEM.
PROBLEM 8: INDOOR BLOWER FAILS TO OPERATE IN COOLING, HEATING, OR CONTINUOUS
FAN MODE
Condition
Possible Cause
Corrective Action/Comments
8.0
- Indoor blower fails to operate in
continuous fan, cooling, or heating
mode.
8.1.1
Miswiring of furnace or improper
connections at control or indoor
blower motor.
ACTION 1- Correct wiring and/or replace any
loose connections. Check for correct wiring
and loose connections.
8.1.2
120V is not being supplied to the
indoor air blower or blower motor
failure.
ACTION 1 - Check for 120V at the various calls
for indoor blower by energizing Y, G,
and W individually on the low voltage ter-
minal strip. Note that when W is ener-
gized, the blower is delayed 45 seconds. If
there is 120V to each motor tap but the blow-
er does not operate, replace the motor.
8.1.3
Defective control board
ACTION 1 - If there is not 120V when Y,
G, or W is energized, replace the con-
trol.
PROBLEM 9: RF STATIC DURING TIME FOR IGNITION
Condition
Possible Cause
Corrective Action/Comments
9.0
- AM radio interference.
9.1.2
Ignitor operation
ACTION 1 - Call Technical Support, Dallas.