Surelight Control Board; Diagnostic Codes; Surelight Control Terminal Designations; Flame Sensor To Burner Gap - Lennox G24M SERIES Unit Information

SURELIGHT CONTROL BOARD

LATE MODEL G24M UNITS
FIGURE 6
MAKE SURE TO ID LED'S CORRECTLY: REFER TO INSTALLATION INSTRUCTIONS FOR CONTROL BOARD LAYOUT.
LED #1
SIMULTANEOUS
SLOW FLASH
SIMULTANEOUS FAST SIMULTANEOUS FAST
FLASH
SLOW FLASH
OFF
ALTERNATING SLOW ALTERNATING SLOW
FLASH
SLOW FLASH
ON
ON
ON
OFF
FAST FLASH
SLOW FLASH
ALTERNATING FAST ALTERNATING FAST
FLASH
NOTE - Slow flash equals 1 Hz (one flash per second). Fast flash equals 3 Hz (three flashes per second). Drop out flame sense current < 0.15 microAmps

DIAGNOSTIC CODES

LED #2
SIMULTANEOUS
SLOW FLASH
Normal operation - signaled when heating demand initiated at thermostat.
FLASH
Primary or Secondary limit open. Units with board 63K8901 or 24L85: Limit must
close within 5 trials for ignition or board goes into one hour limit Watchguard.
ON
Units with board 56L83 or 97L48: Limit must close within 3 minutes or board
Pressure switch open or has opened 5 times during a single call for heat; OR:
Blocked inlet/exhaust vent; OR: Condensate line blocked; OR: Pressure switch
SLOW FLASH
FLASH
OFF
SLOW FLASH
ON
OFF
ON
SLOW FLASH
Low flame signal. Measures below .7 microAmps. Replace flame sense rod.
FAST FLASH
Improper main ground or line voltage below 75 volts; OR: Broken ignitor; OR:
FLASH

SURELIGHT CONTROL TERMINAL DESIGNATIONS

ACB COOL
ACB HEAT
PARK
ACB LOW
ACC
TX
HOT
HTG ACC
NEUTRALS
24VAC HOT
24VAC RTN
FLAME SENSE
NORMAL FLAME SIGNAL > 0.7 MICROAMPS
LOW FLAME SIGNAL
MINIMUM FLAME SIGNAL < 0.15 MICROAMPS

FLAME SENSOR TO BURNER GAP

1/4 in. 7 mm
¦ 1/32 in. 0.79
BURNER
SIDE VIEW
TABLE 2
DESCRIPTION
Power - Normal operation
Also signaled during cooling and continues fan.
goes into one hour limit Watchguard.
closed prior to activation of combustion air blower.
Watchguard - burners fail to ignite.
Flame sensed without gas valve energized.
Rollout switch open. OR: 9 pin connector improperly attached.
Circuit board failure or control wired incorrectly.
Main power polarity reversed. Switch line and neutral.
Open ignitor circuit.
Page 9
TABLE 1
Blower - Cooling Speed (Line Volt)
Blower - Heating Speed (Line Volt)
Alternate Blower Speeds (Dead)
Continuous Low Speed Blower
Accessory Terminal (Line Volt)
120VAC Hot to Transformer
120VAC Hot Input
Heat Only Accessory (Line Volt)
120VAC Neutrals
24VAC Hot from Transformer
24VAC Return from Transformer
Flame Sense Terminal
< 0.7 MICROAMPS
11/16 in. 18 mm
¦ 1/32 in. 0.79
mm
3/16 in.
4.7 mm
FLAME
SENSOR
END VIEW
FIGURE 7
mm