Page 35
Repair Parts List
The following repair parts are available through independent Lennox dealers. When ordering parts, include the complete
furnace model number listed on the unit rating plate. Example: G32VQ3-75-5.
Cabinet Parts
Cabinet cap
Blower panel
Upper access panel
Control Panel Parts
TwoĆstage, variable-speed SureLight control board
Transformer
Circuit breaker
Door interlock switch
Blower Parts
Blower wheel
Motor
Belly-band assembly
Power choke
Blower housing cutĆoff plate
Blower housing
Heating Parts
Heat exchanger/coil assembly
Gas manifold
Main burner orifices
Main burners
TwoĆstage gas valve
Ignitor
Primary limit control
Flame rollout switch
Filter and filter rack assembly
Flue transition
Pressure switch - high fire (-75 only)
Pressure switch - low fire
Flame sensor
Sight glass and grommet
Rubber boot trap
Foam manifold gaskets
TwoĆspeed combustion air blower
Condensate pipe plug and adapter
Cold end header (collector) box
Integrated Control Board Diagnostic Codes
DIAGNOSTIC CODES
Diagnostic LEDs are labeled DS1 and DS2. See figure 29 for location of diagnostic LEDs.
DS1
DS2
DESCRIPTION
SIMULTANEOUS
SLOW FLASH
SIMULTANEOUS
SLOW FLASH
Power on - Normal operation.
Also signaled during cooling and continuous fan.
SIMULTANEOUS
FAST FLASH
SIMULTANEOUS
FAST FLASH
Normal operation - signaled when heating demand initiated at thermostat.
SLOW FLASH
ON
Primary limit or rollout limit switch open. Limits must close within 3 minutes or unit
goes into 1 hour Watchguard.
OFF
SLOW FLASH
Low-fire pressure switch open;
OR: Blocked inlet/exhaust vent;
OR: Low-fire pressure switch closed prior to activation of combustion air inducer.
OFF
FAST FLASH
High-fire pressure switch open (G32V-75 only);
OR: Blocked inlet/exhaust vent;
OR: High-fire pressure switch closed prior to activation of combustion air inducer.
ALTERNATING
SLOW FLASH
ALTERNATING
SLOW FLASH
Watchguard -- burners failed to ignite; OR limit open more than 3 minutes;
OR lost flame sense 5 times in one heating cycle;
OR pressure switch opened 5 times in one heating cycle.
SLOW FLASH
OFF
Flame sensed without gas valve energized.
ON
ON
ON
ON
ON
OFF
Circuit board failure or control wired incorrectly. Check 24 and 115 volts to board.
OFF
ON
Circuit board failure or control wired incorrectly. Check 24 and 115 volts to board.
FAST FLASH
SLOW FLASH
Main power polarity reversed. Switch line and neutral.
SLOW FLASH
FAST FLASH
Low flame signal. Measures below .7 microAmps. Replace flame sense rod.
ALTERNATING
FAST FLASH
ALTERNATING
FAST FLASH
The following conditions are sensed during the ignitor warm-up period only:
1) Improper main ground;
2) Broken ignitor; OR: Open ignitor circuit;
3) Line voltage below 75 volts.
(If voltage lower than 75 volts prior to ignitor warmĆup, control will signal waiting on
call from thermostat, and will not respond.
NOTE - Slow flash rate equals 1 Hz (one flash per second). Fast flash rate equals 3 Hz (three flashes per second).
Minimum flame sense current = 0.15-0.17 microAmps.
