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RAPID FLASH

Lennox · SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace

Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace RAPID FLASH Error Fix: Flame Signal Marginal

The LED flashes rapidly (approximately 4 times per second) without pausing. The flame signal from the flame sensor is below the minimum threshold but the burner is still lit. The flame sensor rod may be dirty (carbon buildup), cracked, or improperly positioned. Clean the flame sensor with fine emery cloth or steel wool. Flame current should read ≥1.0 microamps DC (ideal is 2.0–6.0 µA).

Medium severity2 fixes available

Quick Answer

Error RAPID FLASH on the Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace means: Flame Signal Marginal. The top-ranked community fix is “Test and Replace Flame Sensor if Faulty” (medium difficulty, ~45 min, DIY cost: $10-$20). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · furnace

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

When to Call a Professional

While many furnace repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $150-$250.

Other Lennox Models with Error RAPID FLASH

EL296V Elite Series 96% AFUE Two-Stage Variable Speed Gas Furnace

furnace · 2 fixes

ML196E Merit Series 96% AFUE Single-Stage Gas Furnace

furnace · 2 fixes

SL280V Dave Lennox Signature Collection 80% AFUE Variable Speed Gas Furnace

furnace · 2 fixes

Other Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace Error Codes

1 FLASH

No Previous Fault Code Stored

2 fixes

10 FLASHES

Blower Motor Calibration Fault

2 fixes

11 FLASHES

Auxiliary Limit Switch Open

Inducer Motor Fault

Communicating System Fault

2 fixes

2 FLASHES

System Lockout — Retries Exhausted

2 fixes

3 FLASHES

Pressure Switch Stuck Closed

2 fixes

4 FLASHES

Pressure Switch Open — Did Not Close

2 fixes

People Also Ask About Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace Error RAPID FLASH

What does error code RAPID FLASH mean on a Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace?

Error code RAPID FLASH on the Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace means: Flame Signal Marginal. The LED flashes rapidly (approximately 4 times per second) without pausing. The flame signal from the flame sensor is below the minimum threshold but the burner is still lit. The flame sensor rod may be dirty (carbon buildup), cracked, or improperly positioned. Clean the flame sensor with fine emery cloth or steel wool. Flame current should read ≥1.0 microamps DC (ideal is 2.0–6.0 µA).

How do I fix error code RAPID FLASH on my Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace?

The most successful fix is "Test and Replace Flame Sensor if Faulty" (medium difficulty, ~45 minutes). Estimated DIY cost: $10-$20. HomeMD has 2 community-ranked fixes for this error.

Is error code RAPID FLASH on a Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace serious?

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Can I fix Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace error RAPID FLASH myself?

Yes — the top-ranked community fix ("Test and Replace Flame Sensor if Faulty") is rated medium difficulty and takes about 45 minutes. Tools needed: T20 Torx screwdriver, Multimeter (microamps DC).

How much does it cost to repair Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace error RAPID FLASH?

DIY cost: $10-$20. Professional repair typically costs $150-$250. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace have?

The Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace has 8 other known error codes, including: 1 FLASH (No Previous Fault Code Stored), 10 FLASHES (Blower Motor Calibration Fault), 11 FLASHES (Auxiliary Limit Switch Open), 12 FLASHES (Inducer Motor Fault), 13 FLASHES (Communicating System Fault), and 3 more.

Which other Lennox models have the RAPID FLASH error?

Error code RAPID FLASH also appears on 3 other Lennox models: EL296V Elite Series 96% AFUE Two-Stage Variable Speed Gas Furnace, ML196E Merit Series 96% AFUE Single-Stage Gas Furnace, SL280V Dave Lennox Signature Collection 80% AFUE Variable Speed Gas Furnace. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace have?

The Lennox SL297NV Dave Lennox Signature Collection 97% AFUE Modulating Variable Speed Gas Furnace has 8 other known error codes:

1 FLASH — No Previous Fault Code Stored (2 fixes)
10 FLASHES — Blower Motor Calibration Fault (2 fixes)
11 FLASHES — Auxiliary Limit Switch Open (2 fixes)
12 FLASHES — Inducer Motor Fault (2 fixes)
13 FLASHES — Communicating System Fault (2 fixes)
2 FLASHES — System Lockout — Retries Exhausted (2 fixes)
3 FLASHES — Pressure Switch Stuck Closed (2 fixes)
4 FLASHES — Pressure Switch Open — Did Not Close (2 fixes)

Which other Lennox models have the RAPID FLASH error?

Error code RAPID FLASH also appears on 3 other Lennox models:

EL296V Elite Series 96% AFUE Two-Stage Variable Speed Gas Furnace (furnace) · 2 fixes
ML196E Merit Series 96% AFUE Single-Stage Gas Furnace (furnace) · 2 fixes
SL280V Dave Lennox Signature Collection 80% AFUE Variable Speed Gas Furnace (furnace) · 2 fixes

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