Lennox CBX27UH Lennox Variable Speed Air Handler EVAPORATOR COIL DIRTY Error Fix: Indoor Coil Dirty / Restricted

Evaporator coil is dirty or blocked with particulate, reducing heat transfer and airflow. Symptoms: reduced capacity, icing in cooling mode, high static pressure. Use foam coil cleaner (no-rinse type) or gentle water rinse. Do NOT use pressure washer on delicate aluminum fins. A dirty coil can reduce capacity by 20–30%.

Medium severity2 fixes available✨ Free fix available

Quick Answer

Error EVAPORATOR COIL DIRTY on the Lennox CBX27UH Lennox Variable Speed Air Handler means: Indoor Coil Dirty / Restricted. The top-ranked community fix is “Deep Clean or Replace Evaporator Coil” (hard difficulty, ~120 min, DIY cost: $0). 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: $400-$600.

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

FLASHING GREEN

Normal — Blower Running

2 fixes

FLASHING YELLOW

High Limit — Electric Heat

No Power

Electric Heat Strip Sequencer Failure

Normal — Standby

Control Board Fault

People Also Ask About Lennox CBX27UH Lennox Variable Speed Air Handler Error EVAPORATOR COIL DIRTY

What does error code EVAPORATOR COIL DIRTY mean on a Lennox CBX27UH Lennox Variable Speed Air Handler?

Error code EVAPORATOR COIL DIRTY on the Lennox CBX27UH Lennox Variable Speed Air Handler means: Indoor Coil Dirty / Restricted. Evaporator coil is dirty or blocked with particulate, reducing heat transfer and airflow. Symptoms: reduced capacity, icing in cooling mode, high static pressure. Use foam coil cleaner (no-rinse type) or gentle water rinse. Do NOT use pressure washer on delicate aluminum fins. A dirty coil can reduce capacity by 20–30%.

How do I fix error code EVAPORATOR COIL DIRTY on my Lennox CBX27UH Lennox Variable Speed Air Handler?

The most successful fix is "Deep Clean or Replace Evaporator Coil" (hard difficulty, ~120 minutes). This fix costs nothing. HomeMD has 2 community-ranked fixes for this error.

Is error code EVAPORATOR COIL DIRTY 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 EVAPORATOR COIL DIRTY myself?

Yes — the top-ranked community fix ("Deep Clean or Replace Evaporator Coil") is rated hard difficulty and takes about 120 minutes. Tools needed: T20 Torx screwdriver, Soft coil brush, Garden sprayer, Multimeter.

How much does it cost to repair Lennox CBX27UH Lennox Variable Speed Air Handler error EVAPORATOR COIL DIRTY?

DIY cost: $0. Professional repair typically costs $400-$600. 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), FLASHING GREEN (Normal — Blower Running), FLASHING YELLOW (High Limit — Electric Heat), 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)
FLASHING GREEN — Normal — Blower Running (2 fixes)
FLASHING YELLOW — High Limit — Electric Heat (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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