About FurnaceCodes

FurnaceCodes is an independent informational resource dedicated to helping homeowners understand furnace error codes. We are not affiliated with, endorsed by, or sponsored by any furnace manufacturer.

What We Cover

When your furnace displays an error code, it can be hard to know what it means or what to do next. Manufacturer manuals are often difficult to find online, and the information is scattered across forums and service bulletins. FurnaceCodes organizes that information in one place, by brand and model.

As of 2026, this site covers 12 furnace brands, 37 models, and 785 individual error code entries — each with a description of the fault, likely causes, and guidance on whether it's a DIY-approachable fix or requires a licensed technician.

Our Data Sources

Every error code on this site is sourced from publicly available manufacturer documentation: installation manuals, service manuals, and technical service bulletins published by the furnace manufacturer or its authorized distributors. We do not rely on forums, third-party repair guides, or general HVAC advice as primary sources.

Of the 37 models covered, 37 have been verified against a specific manufacturer manual. Each verified model page displays a "Verified" badge and links to the source document. Unverified models are labeled accordingly and are cross-referenced against related models that share the same control board.

Brands covered: Amana, American Standard, Bryant, Carrier, Coleman, Goodman, Lennox, Payne, Rheem, Ruud, Trane, York.

How We Verify Information

Before any error code page goes live, we follow the same process for every model:

1. Locate the manual — We find the manufacturer's service manual or installation manual for the specific model. We work from the original document, not summaries or third-party guides.
2. Read the source — We go through the relevant sections and record the facts directly: what each code means, what causes it, how severe it is, and whether a homeowner can address it safely. We keep verbatim excerpts so we can check our work.
3. Write only what the manual supports — Page descriptions, causes, and repair guidance are written strictly from what the manual says. If the manual doesn't address something, we don't add it.
4. Apply safety rules — We check that nothing on the page contradicts our safety standards: no DIY steps for gas valves or heat exchangers, no unsafe techniques, no severity claims the manual doesn't support.
5. Review before publishing — Pages are reviewed for factual accuracy, readability, and consistency with related models before going live.

Editorial Standards

• Source-traceable facts only — Every specific claim about a code (its meaning, causes, severity) must trace to a manufacturer document. We do not publish guesses or "commonly reported" information that cannot be verified.
• Conservative DIY guidance — A code is marked DIY-approachable only when the likely fix (cleaning a flame sensor, replacing a filter, clearing a blocked exhaust vent) is low-risk and widely recommended in manufacturer documentation. Anything involving gas valves, heat exchangers, inducer motors, or electrical components is marked as requiring a licensed technician.
• No gas safety shortcuts — Pages never instruct users to bypass safety switches or ignore lockout codes. If you smell gas, we direct you to leave the home and call your gas utility immediately — before any troubleshooting.
• Severity is manufacturer-defined — We do not downgrade a fault's severity to make it sound more approachable. If the manufacturer classifies a fault as safety-critical, we reflect that.
• Transparency about limitations — When a code applies only to specific production runs, firmware versions, or control board revisions, we say so. When we cannot confirm applicability to a specific unit, we recommend consulting the manual or a technician.
• Affiliate disclosure — This site participates in affiliate programs (including Amazon Associates and others). Product links may earn a commission at no cost to you. Affiliate relationships do not influence which parts or repairs we recommend — those decisions are based solely on manufacturer documentation and standard HVAC practice.

What We Don't Cover

FurnaceCodes is a reference for interpreting error codes. It is not a substitute for professional diagnosis. We do not provide:

• Diagnosis of mechanical failures beyond what the error code indicates
• Advice on gas line sizing, venting design, or ductwork installation
• Warranty determination or coverage advice
• Part compatibility beyond what is specified in manufacturer documentation
• Emergency repair guidance — if your furnace poses a safety risk, turn it off and call a licensed HVAC technician

Corrections Policy

If you find an error — a wrong code description, an incorrect severity rating, a mislabeled DIY flag, or anything that contradicts the manufacturer's documentation — please let us know. We take corrections seriously and will review and update the relevant page promptly.

To report a correction, contact us. Include the page URL, the specific claim you believe is incorrect, and the source you're referencing if you have it. We aim to respond within 5 business days.

Contact Us

Have a question, feedback, or a model you'd like to see added? Email us at [email protected].

Disclaimer

The information on this site is provided for general informational purposes only. It is not a substitute for professional HVAC diagnosis and repair. Always consult your furnace's owner manual and a licensed HVAC technician before attempting any repairs. See our full Terms of Use.