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SOLID RED

Lennox · CBX27UH Lennox Variable Speed Air Handler

Lennox CBX27UH Lennox Variable Speed Air Handler SOLID RED Error Fix: Control Board Fault

The air handler control board has an internal failure. Verify power supply first — transformer provides 24 VAC and line voltage is correct (208/230 VAC). Board needs replacement if power is verified.

critical2 fixes available✨ Free fix available

Quick Answer

Error SOLID RED on the Lennox CBX27UH Lennox Variable Speed Air Handler means: Control Board Fault. The top-ranked community fix is “Replace the Faulty Air Handler Control Board” (hard difficulty, ~90 min, DIY cost: $20-$40). 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: $300-$450.

Other Lennox Models with Error SOLID RED

ML14XC1 Merit Series 14 SEER Single-Stage Air Conditioner

air_conditioner · 2 fixes

XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner

air_conditioner · 2 fixes

XC25 Dave Lennox Signature Collection 26 SEER Variable-Capacity Air Conditioner

air_conditioner · 2 fixes

XP21 Dave Lennox Signature Collection 20 SEER Heat Pump

heat_pump · 2 fixes

XP25 Dave Lennox Signature Collection Variable-Capacity Heat Pump

heat_pump · 2 fixes

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

Electric Heat Strip Sequencer Failure

2 fixes

SOLID GREEN

Normal — Standby

2 fixes

People Also Ask About Lennox CBX27UH Lennox Variable Speed Air Handler Error SOLID RED

What does error code SOLID RED mean on a Lennox CBX27UH Lennox Variable Speed Air Handler?

Error code SOLID RED on the Lennox CBX27UH Lennox Variable Speed Air Handler means: Control Board Fault. The air handler control board has an internal failure. Verify power supply first — transformer provides 24 VAC and line voltage is correct (208/230 VAC). Board needs replacement if power is verified.

How do I fix error code SOLID RED on my Lennox CBX27UH Lennox Variable Speed Air Handler?

The most successful fix is "Replace the Faulty Air Handler Control Board" (hard difficulty, ~90 minutes). Estimated DIY cost: $20-$40. HomeMD has 2 community-ranked fixes for this error.

Is error code SOLID RED on a Lennox CBX27UH Lennox Variable Speed Air Handler serious?

This error is rated critical severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Can I fix Lennox CBX27UH Lennox Variable Speed Air Handler error SOLID RED myself?

Yes — the top-ranked community fix ("Replace the Faulty Air Handler Control Board") is rated hard difficulty and takes about 90 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Camera or smartphone for photos.

How much does it cost to repair Lennox CBX27UH Lennox Variable Speed Air Handler error SOLID RED?

DIY cost: $20-$40. Professional repair typically costs $300-$450. 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.

Which other Lennox models have the SOLID RED error?

Error code SOLID RED also appears on 5 other Lennox models: ML14XC1 Merit Series 14 SEER Single-Stage Air Conditioner, XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner, XC25 Dave Lennox Signature Collection 26 SEER Variable-Capacity Air Conditioner, XP21 Dave Lennox Signature Collection 20 SEER Heat Pump, XP25 Dave Lennox Signature Collection Variable-Capacity Heat Pump. The fix may vary by model, so check each model's specific page for tailored repair steps.

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)
SEQUENCER FAILURE — Electric Heat Strip Sequencer Failure (2 fixes)
SOLID GREEN — Normal — Standby (2 fixes)

Which other Lennox models have the SOLID RED error?

Error code SOLID RED also appears on 5 other Lennox models:

ML14XC1 Merit Series 14 SEER Single-Stage Air Conditioner (air conditioner) · 2 fixes
XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner (air conditioner) · 2 fixes
XC25 Dave Lennox Signature Collection 26 SEER Variable-Capacity Air Conditioner (air conditioner) · 2 fixes
XP21 Dave Lennox Signature Collection 20 SEER Heat Pump (heat pump) · 2 fixes
XP25 Dave Lennox Signature Collection Variable-Capacity Heat Pump (heat pump) · 2 fixes

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