Lennox CBX27UH Lennox Variable Speed Air Handler SEQUENCER FAILURE Error Fix: Electric Heat Strip Sequencer Failure

Heat strip sequencer relays have failed. Sequencers stage electric heat strips on in sequence to prevent large inrush current. Symptoms: some strips work but others don't, intermittent heating, burning smell. Test each relay for continuity when energized. Replace failed sequencers.

Medium severity2 fixes available✨ Free fix available

Quick Answer

Error SEQUENCER FAILURE on the Lennox CBX27UH Lennox Variable Speed Air Handler means: Electric Heat Strip Sequencer Failure. The top-ranked community fix is “Test and Replace Faulty Heat Strip Sequencer Relays” (hard difficulty, ~90 min, DIY cost: $15-$25). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · air handler

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 air handler 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: $200-$350.

Other Lennox CBX27UH Lennox Variable Speed Air Handler Error Codes

AH BLOWER MOTOR FAIL

Blower Motor Failure

2 fixes

DRAIN PAN OVERFLOW

Condensate Drain Pan Overflow

2 fixes

EVAPORATOR COIL DIRTY

Indoor Coil Dirty / Restricted

2 fixes

FLASHING GREEN

Normal — Blower Running

2 fixes

FLASHING YELLOW

High Limit — Electric Heat

No Power

Normal — Standby

Control Board Fault

People Also Ask About Lennox CBX27UH Lennox Variable Speed Air Handler Error SEQUENCER FAILURE

What does error code SEQUENCER FAILURE mean on a Lennox CBX27UH Lennox Variable Speed Air Handler?

Error code SEQUENCER FAILURE on the Lennox CBX27UH Lennox Variable Speed Air Handler means: Electric Heat Strip Sequencer Failure. Heat strip sequencer relays have failed. Sequencers stage electric heat strips on in sequence to prevent large inrush current. Symptoms: some strips work but others don't, intermittent heating, burning smell. Test each relay for continuity when energized. Replace failed sequencers.

How do I fix error code SEQUENCER FAILURE on my Lennox CBX27UH Lennox Variable Speed Air Handler?

The most successful fix is "Test and Replace Faulty Heat Strip Sequencer Relays" (hard difficulty, ~90 minutes). Estimated DIY cost: $15-$25. HomeMD has 2 community-ranked fixes for this error.

Is error code SEQUENCER FAILURE on a Lennox CBX27UH Lennox Variable Speed Air Handler 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 CBX27UH Lennox Variable Speed Air Handler error SEQUENCER FAILURE myself?

Yes — the top-ranked community fix ("Test and Replace Faulty Heat Strip Sequencer Relays") is rated hard difficulty and takes about 90 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Needle-nose pliers.

How much does it cost to repair Lennox CBX27UH Lennox Variable Speed Air Handler error SEQUENCER FAILURE?

DIY cost: $15-$25. Professional repair typically costs $200-$350. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Lennox CBX27UH Lennox Variable Speed Air Handler have?

The Lennox CBX27UH Lennox Variable Speed Air Handler has 8 other known error codes, including: AH BLOWER MOTOR FAIL (Blower Motor Failure), DRAIN PAN OVERFLOW (Condensate Drain Pan Overflow), EVAPORATOR COIL DIRTY (Indoor Coil Dirty / Restricted), FLASHING GREEN (Normal — Blower Running), FLASHING YELLOW (High Limit — Electric Heat), and 3 more.

What other error codes does the Lennox CBX27UH Lennox Variable Speed Air Handler have?

The Lennox CBX27UH Lennox Variable Speed Air Handler has 8 other known error codes:

AH BLOWER MOTOR FAIL — Blower Motor Failure (2 fixes)
DRAIN PAN OVERFLOW — Condensate Drain Pan Overflow (2 fixes)
EVAPORATOR COIL DIRTY — Indoor Coil Dirty / Restricted (2 fixes)
FLASHING GREEN — Normal — Blower Running (2 fixes)
FLASHING YELLOW — High Limit — Electric Heat (2 fixes)
NO LIGHT — No Power (2 fixes)
SOLID GREEN — Normal — Standby (2 fixes)
SOLID RED — Control Board Fault (2 fixes)

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