Lennox Furnace: Furnace will not run (no heat) – Lennox SL297NV

Furnace will not run (no heat) - Lennox SL297NV on a Lennox furnace: Basic checks from the manual when the SL297UHNV does not operate.

Homeowner with a furnace problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Applies to: SL297UHNV

Common causes of furnace will not run (no heat) - lennox sl297nv

• No heat call
• Access panel off
• Power off
• Dirty filter
• Gas off
• Ignition lockout (Watchguard)

How to fix furnace will not run (no heat) - lennox sl297nv: step by step

1. Confirm the thermostat is calling for heat.
2. Make sure access panels are secure.
3. Check main disconnect, fuses and breakers.
4. Check the filter; a plugged filter will trip the limit (E250).
5. Confirm gas is on at the meter and both the main and internal manual valves are open.
6. Check the 7-segment display for an E-code; if the unit is in Watchguard lockout (auto-retry after 60 minutes), move the thermostat from Heat to Off and back to Heat to restart, and inspect for blockages if it locks out again.

If the unit shows an error code, look it up: Lennox Furnace codes

Models

Lennox EL195UHNE

EL195UH040NE36BEL195UH060NE36BEL195UH080NE48CEL195UH100NE60C

EL296UHV

EL296UH045XV36BEL296UH070XV36BEL296UH090XV36CEL296UH090XV48CEL296UH090XV60CEL296UH110XV48CEL296UH110XV60CEL296UH135XV60D

Lennox ML180UHE

ML180UH045E36AKML180UH045XE36AKML180UH070E36AKML180UH070E36BKML180UH070XE36AKML180UH070XE36BKML180UH090E48BKML180UH090E60CKML180UH090XE48BKML180UH110E60CKML180UH110XE60CKML180UH135E60DK

Lennox SL280UHV

SL280UH060NV36ASL280UH070V36ASL280UH080NV48BSL280UH080NV60CSL280UH090V36BSL280UH090V48BSL280UH090V60CSL280UH100NV60CSL280UH110V60CSL280UH135V60D

Lennox SL297NV

SL297UH040NV36BSL297UH060NV36BSL297UH080NV48CSL297UH080NV60C