Lennox · Furnace

P Program unit size (button menu)

Menu / mode display EL296UHVLennox SL280UHVLennox SL280UHNVLennox SL297NV

What the display is showing

Variable speed models only. Used to set the furnace size code after replacing the control.

Applies to: EL296UHV(X) with control 103130-XX or 107045-XX

What to do

Thermostat off, control idle. Hold the button until a solid P shows, release.
P flashes for 90 seconds. Hold the button again and release when the right size code shows (each shows for 3 seconds).
The code then flashes for 10 seconds. Within that time hold the button 5 seconds to store it.
Cycle 24 V power to confirm. If the time runs out or the hold is too short, nothing is changed.

Settings for these units

Recommended filter size by cabinet width · EL296UHV

Cabinet width	Side return	Bottom return
17-1/2 in.	16 x 25 x 1 in. (1)	16 x 25 x 1 in. (1)
21 in.	16 x 25 x 1 in. (1)	20 x 25 x 1 in. (1)
24-1/2 in.	16 x 25 x 1 in. (2)	24 x 25 x 1 in. (1)

Number in brackets is the quantity of filters.

Filters are field supplied and installed outside the furnace; inspect monthly.

Recommended filter size by cabinet width · Lennox SL280UHV

Cabinet width	Side return	Bottom return
14-1/2 in.	16 x 25 x 1 in. (1)	14 x 25 x 1 in. (1)
17-1/2 in.	16 x 25 x 1 in. (1)	16 x 25 x 1 in. (1)
21 in.	16 x 25 x 1 in. (1)	20 x 25 x 1 in. (1)
24-1/2 in.	16 x 25 x 1 in. (2)	24 x 25 x 1 in. (1)

Number in brackets is filter quantity; filters are field supplied.

Never run the unit without a filter installed.

Filter sizes by cabinet width · Lennox SL297NV

Models that show this code

22 models in EL296UHV, Lennox SL280UHV, Lennox SL280UHNV, Lennox SL297NV

EL296UH045XV36BEL296UH070XV36BEL296UH090XV36CEL296UH090XV48CEL296UH090XV60CEL296UH110XV48CEL296UH110XV60CEL296UH135XV60DSL280UH060NV36ASL280UH070V36ASL280UH080NV48BSL280UH080NV60CSL280UH090V36BSL280UH090V48BSL280UH090V60CSL280UH100NV60CSL280UH110V60CSL280UH135V60DSL297UH040NV36BSL297UH060NV36BSL297UH080NV48CSL297UH080NV60C

Other codes on the same units

. Idle - no call
= Two bars - soft disable
A Blower airflow setting
E Error recall mode (button menu)
F Flame signal mode (button menu)
Power-up size code Unit size code shown at power-up (variable speed)
U Discharge air temperature
c Clear stored errors (inside error recall)

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Source: Lennox EL296UHV(X) Unit Information, Corp 1125-L5 (rev. 03/2022), Tables 4-5 (diagnostic modes and LED codes), printed p.32-33. Summarized in our own words; check the original manual for your model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.