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CODE-24

Carrier · Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence

Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence CODE-24 Error Fix: Infinity Code 24 — Secondary Voltage Fuse Blown

The Infinity System Control displays "Code 24" indicating the secondary (24V) fuse on the furnace control board has blown. The 24V fuse protects the low-voltage control circuit. Common causes: a short circuit in the thermostat wiring (the thermostat wire insulation can be damaged by attic heat, rodents, or staples), a short in the contactor coil on the outdoor unit, or a wiring fault during a thermostat installation. To fix: locate the glass or automotive-style fuse on the furnace control board (typically 3A or 5A). Replace with the same amperage fuse. If the new fuse blows immediately, there is an active short in the 24V wiring — disconnect the thermostat wire at the furnace and replace the fuse. If it holds, the short is in the thermostat wiring or thermostat. Reconnect wires one at a time to identify the shorted circuit.

Medium severity2 fixes available

Quick Answer

Error CODE-24 on the Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence means: Infinity Code 24 — Secondary Voltage Fuse Blown. The top-ranked community fix is “Test and Repair Thermostat and Outdoor Unit Wiring Short” (medium difficulty, ~60 min, DIY cost: $10-$20). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · furnace

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 furnace 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: $150-$300.

Other Carrier Models with Error CODE-24

Carrier 59TN6 Infinity 96 Two-Stage 96% AFUE Gas Furnace with Variable-Speed Blower

furnace · 2 fixes

Other Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence Error Codes

CODE-21

Infinity Code 21 — Gas Heating Lockout

2 fixes

CODE-22

Infinity Code 22 — Abnormal Flame-Proving Signal

2 fixes

CODE-23

Infinity Code 23 — Pressure Switch Fault

2 fixes

CODE-26

Infinity Code 26 — Line Voltage Limit Circuit Open

2 fixes

CODE-41

Infinity Code 41 — Blower Motor Fault

2 fixes

CODE-42

Infinity Code 42 — Inducer Motor Fault

2 fixes

CODE-43

Infinity Code 43 — Low Flame Signal / Dirty Flame Sensor

2 fixes

CODE-44

Infinity Code 44 — Blower Calibration Fault

2 fixes

People Also Ask About Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence Error CODE-24

What does error code CODE-24 mean on a Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence?

Error code CODE-24 on the Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence means: Infinity Code 24 — Secondary Voltage Fuse Blown. The Infinity System Control displays "Code 24" indicating the secondary (24V) fuse on the furnace control board has blown. The 24V fuse protects the low-voltage control circuit. Common causes: a short circuit in the thermostat wiring (the thermostat wire insulation can be damaged by attic heat, rodents, or staples), a short in the contactor coil on the outdoor unit, or a wiring fault during a thermostat installation. To fix: locate the glass or automotive-style fuse on the furnace control board (typically 3A or 5A). Replace with the same amperage fuse. If the new fuse blows immediately, there is an active short in the 24V wiring — disconnect the thermostat wire at the furnace and replace the fuse. If it holds, the short is in the thermostat wiring or thermostat. Reconnect wires one at a time to identify the shorted circuit.

How do I fix error code CODE-24 on my Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence?

The most successful fix is "Test and Repair Thermostat and Outdoor Unit Wiring Short" (medium difficulty, ~60 minutes). Estimated DIY cost: $10-$20. HomeMD has 2 community-ranked fixes for this error.

Is error code CODE-24 on a Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence 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 Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence error CODE-24 myself?

Yes — the top-ranked community fix ("Test and Repair Thermostat and Outdoor Unit Wiring Short") is rated medium difficulty and takes about 60 minutes. Tools needed: Multimeter, Wire strippers, HVAC-rated thermostat wire, Screwdrivers (Phillips and flathead).

How much does it cost to repair Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence error CODE-24?

DIY cost: $10-$20. Professional repair typically costs $150-$300. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence have?

The Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence has 8 other known error codes, including: CODE-21 (Infinity Code 21 — Gas Heating Lockout), CODE-22 (Infinity Code 22 — Abnormal Flame-Proving Signal), CODE-23 (Infinity Code 23 — Pressure Switch Fault), CODE-26 (Infinity Code 26 — Line Voltage Limit Circuit Open), CODE-41 (Infinity Code 41 — Blower Motor Fault), and 3 more.

Which other Carrier models have the CODE-24 error?

Error code CODE-24 also appears on 1 other Carrier model: Carrier 59TN6 Infinity 96 Two-Stage 96% AFUE Gas Furnace with Variable-Speed Blower. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence have?

The Carrier Carrier 59MN7 Infinity 98 Modulating 98.5% AFUE Gas Furnace with Greenspeed Intelligence has 8 other known error codes:

CODE-21 — Infinity Code 21 — Gas Heating Lockout (2 fixes)
CODE-22 — Infinity Code 22 — Abnormal Flame-Proving Signal (2 fixes)
CODE-23 — Infinity Code 23 — Pressure Switch Fault (2 fixes)
CODE-26 — Infinity Code 26 — Line Voltage Limit Circuit Open (2 fixes)
CODE-41 — Infinity Code 41 — Blower Motor Fault (2 fixes)
CODE-42 — Infinity Code 42 — Inducer Motor Fault (2 fixes)
CODE-43 — Infinity Code 43 — Low Flame Signal / Dirty Flame Sensor (2 fixes)
CODE-44 — Infinity Code 44 — Blower Calibration Fault (2 fixes)

Which other Carrier models have the CODE-24 error?

Error code CODE-24 also appears on 1 other Carrier model:

Carrier 59TN6 Infinity 96 Two-Stage 96% AFUE Gas Furnace with Variable-Speed Blower (furnace) · 2 fixes

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