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ThefollowingrepairpartsareavailablethroughLennoxdealers.Whenorderingparts,includethecompletefurnacemodel
numberlistedontheCSAInternationalnameplate--Example:G50UH(X)-24A-045-8,
CabinetParts
Upperaccesspanel
Blowerpanel
Topcap
ControlPanelParts
Transformer
SureLight®ignitionboard
Doorinterlockswitch
Circuitbreaker
BlowerParts
Blowerwheel
Motor
Motormountingframe
Motorcapacitor
Blowerhousingcutoffplate
HeatingParts
FlameSensor
Heatexchangerassembly
Gasmanifold
Combustionairinducer
Gasvalve
Mainburnercluster
Mainburnerorifices
Pressureswitch
Ignitor
Primarylimitcontrol
Flamerolloutswitch
Secondarylimit(notusedon24A-45-1)
DIAGNOSTIC CODES
Make sure to Identify LED'S Correctly.
Refer to Installation Instructions for control board layout,
DSl DS2 DESCRIPTION
(Red or Green) (Green)
SIMULTANEOUS SIMULTANEOUS Power on -- Normal operation.
SLOW FLASH SLOW FLASH Also signaled during cooling and continuous fan.
SIMULTANEOUS SIMULTANEOUS
Normal operation -- Signaled when heating demand initiated at thermostat.
FAST FLASH FAST FLASH
SLOW FLASH ON Primary or secondary limit switch open. Limit must close within 3 minutes or unit
goes into 1-hour Watchguard.
Pressure switch open;
OR: Blocked inlet/exhaust vent;
OFF SLOW FLASH
OR: Condensate line blocked;
OR: Pressure switch closed prior to activation of combustion air inducer.
ALTERNATING ALTERNATING Watchguard -- Burners failed to ignite, limit open longer than 3 minutes, or flame
SLOW FLASH SLOW FLASH sense lost 5 times in one heating cycle.
SLOW FLASH OFF Flame sensed without gas valve energized.
ON SLOW FLASH Rollout switch open.
ON ON
Circuit board failure or control wired incorrectly. Check 24-volt and 115-volt
ON OFF
connections to board.
OFF ON
FAST FLASH SLOW FLASH Main power polarity reversed. Switch line and neutral. Improper main ground.
SLOW FLASH FAST FLASH Low flame signal. Check flame sensor.
The following conditions are sensed during the ignitor warm-up period only:
ALTERNATING ALTERNATING 1) Improper main ground;
FAST FLASH FAST FLASH 2) Broken ignitor; OR: Open ignitor circuit;
3) Line voltage below 75 volts.
NOTE - Slow flash rate equals 1 Hz (one flash per second). Fast flash rate equals 3 Hz (three flashes per second).
Drop out flame sense current = 0.15 - 0.24 microAmps.
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