Control Signals Low Flame Sense During Heating Mode; Rf Static During Time For Ignition - Lennox G24M SERIES Unit Information

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