Lennox CBX27UH Lennox Variable Speed Air Handler FLASHING YELLOW Error Fix: High Limit — Electric Heat

The electric heat strip high-limit thermostat has tripped. Heat strips overheated due to insufficient airflow. Check air filter, ductwork obstructions, and blower operation. Limit switch will auto-reset once temperature drops.

High severity2 fixes available

Quick Answer

Error FLASHING YELLOW on the Lennox CBX27UH Lennox Variable Speed Air Handler means: High Limit — Electric Heat. The top-ranked community fix is “Test and Replace High Limit Thermostat” (hard difficulty, ~60 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:

This is a high severity error — continued use may cause damage or a safety hazard
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 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

No Power

Electric Heat Strip Sequencer Failure

Normal — Standby

Control Board Fault

People Also Ask About Lennox CBX27UH Lennox Variable Speed Air Handler Error FLASHING YELLOW

What does error code FLASHING YELLOW mean on a Lennox CBX27UH Lennox Variable Speed Air Handler?

Error code FLASHING YELLOW on the Lennox CBX27UH Lennox Variable Speed Air Handler means: High Limit — Electric Heat. The electric heat strip high-limit thermostat has tripped. Heat strips overheated due to insufficient airflow. Check air filter, ductwork obstructions, and blower operation. Limit switch will auto-reset once temperature drops.

How do I fix error code FLASHING YELLOW on my Lennox CBX27UH Lennox Variable Speed Air Handler?

The most successful fix is "Test and Replace High Limit Thermostat" (hard difficulty, ~60 minutes). Estimated DIY cost: $15-$25. HomeMD has 2 community-ranked fixes for this error.

Is error code FLASHING YELLOW on a Lennox CBX27UH Lennox Variable Speed Air Handler serious?

This error is rated high severity. You should address it promptly — continued use could cause damage or safety concerns.

Can I fix Lennox CBX27UH Lennox Variable Speed Air Handler error FLASHING YELLOW myself?

Yes — the top-ranked community fix ("Test and Replace High Limit Thermostat") is rated hard difficulty and takes about 60 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 FLASHING YELLOW?

DIY cost: $15-$25. 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 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), NO LIGHT (No Power), 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)
NO LIGHT — No Power (2 fixes)
SEQUENCER FAILURE — Electric Heat Strip Sequencer Failure (2 fixes)
SOLID GREEN — Normal — Standby (2 fixes)
SOLID RED — Control Board Fault (2 fixes)

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