❄️Air Conditioner

ALERT 61

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

Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner ALERT 61 Error Fix: Low Voltage Detected

The control board has detected 24 VAC control voltage below minimum operating threshold. Causes: undersized or failing transformer, excessive wire run length (voltage drop), too many accessories on the 24V circuit. Measure 24 VAC at control board terminals — should be 24–28 VAC under load.

Medium severity2 fixes available✨ Free fix available

Quick Answer

Error ALERT 61 on the Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner means: Low Voltage Detected. The top-ranked community fix is “Replace Transformer and Inspect 24 VAC Circuit Wiring” (medium difficulty, ~60 min, DIY cost: $15-$20). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · air conditioner

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 conditioner 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: $120-$200.

Other Lennox Models with Error ALERT 61

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

1 FLASH YELLOW

High Pressure Switch Open

2 fixes

2 FLASHES YELLOW

Low Pressure Switch Open

2 fixes

3 FLASHES YELLOW

Compressor Thermal Overload

2 fixes

4 FLASHES YELLOW

Short-Cycle Protection

2 fixes

ALERT 1

Communication Loss — Outdoor Unit

2 fixes

ALERT 11

High Pressure Protection — Outdoor Unit

2 fixes

ALERT 12

Low Pressure Protection — Outdoor Unit

2 fixes

ALERT 14

Compressor Discharge Temperature High

2 fixes

People Also Ask About Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner Error ALERT 61

What does error code ALERT 61 mean on a Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner?

Error code ALERT 61 on the Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner means: Low Voltage Detected. The control board has detected 24 VAC control voltage below minimum operating threshold. Causes: undersized or failing transformer, excessive wire run length (voltage drop), too many accessories on the 24V circuit. Measure 24 VAC at control board terminals — should be 24–28 VAC under load.

How do I fix error code ALERT 61 on my Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner?

The most successful fix is "Replace Transformer and Inspect 24 VAC Circuit Wiring" (medium difficulty, ~60 minutes). Estimated DIY cost: $15-$20. HomeMD has 2 community-ranked fixes for this error.

Is error code ALERT 61 on a Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner 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 XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner error ALERT 61 myself?

Yes — the top-ranked community fix ("Replace Transformer and Inspect 24 VAC Circuit Wiring") is rated medium difficulty and takes about 60 minutes. Tools needed: Phillips screwdriver, Digital multimeter, Wire stripper, Needle nose pliers, Voltage tester.

How much does it cost to repair Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner error ALERT 61?

DIY cost: $15-$20. Professional repair typically costs $120-$200. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner have?

The Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner has 8 other known error codes, including: 1 FLASH YELLOW (High Pressure Switch Open), 2 FLASHES YELLOW (Low Pressure Switch Open), 3 FLASHES YELLOW (Compressor Thermal Overload), 4 FLASHES YELLOW (Short-Cycle Protection), ALERT 1 (Communication Loss — Outdoor Unit), and 3 more.

Which other Lennox models have the ALERT 61 error?

Error code ALERT 61 also appears on 3 other Lennox models: 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 XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner have?

The Lennox XC21 Dave Lennox Signature Collection 21 SEER Variable-Capacity Air Conditioner has 8 other known error codes:

1 FLASH YELLOW — High Pressure Switch Open (2 fixes)
2 FLASHES YELLOW — Low Pressure Switch Open (2 fixes)
3 FLASHES YELLOW — Compressor Thermal Overload (2 fixes)
4 FLASHES YELLOW — Short-Cycle Protection (2 fixes)
ALERT 1 — Communication Loss — Outdoor Unit (2 fixes)
ALERT 11 — High Pressure Protection — Outdoor Unit (2 fixes)
ALERT 12 — Low Pressure Protection — Outdoor Unit (2 fixes)
ALERT 14 — Compressor Discharge Temperature High (2 fixes)

Which other Lennox models have the ALERT 61 error?

Error code ALERT 61 also appears on 3 other Lennox models:

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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