HeatingCodesSafety disclaimer
Call a licensed professional
Gas appliances, venting, combustion air, gas piping, refrigerant circuits and line-voltage wiring can cause fire, explosion, carbon monoxide poisoning, electric shock or serious injury when worked on incorrectly. Many repairs also require a license or permit. HeatingCodes publishes information so you can understand a fault code and speak knowledgeably to a technician. It is not a substitute for a licensed gas fitter, HVAC contractor, plumber or electrician.
The checks we describe as homeowner-safe are limited to things like replacing a furnace filter, opening vents, checking a breaker or power switch, confirming a gas shutoff is open, clearing snow from outdoor terminations you can reach from the ground, and pressing a reset button once. Anything else is for a professional.
Never bypass a safety device
Limit switches, rollout switches, pressure switches, flame sensors and similar parts are there to protect you. Do not jumper, bypass, disconnect, tape over or defeat them, and do not keep resetting a lockout that repeats.
Information may not match your equipment
Fault code definitions differ by manufacturer, product line, control board and production date. Each table on this site states the document and models it covers, but your equipment may differ. The label on your equipment and your owner's or installation manual take priority. Manufacturer documents change, and we cannot guarantee that any page reflects the latest revision.
Calculators
The heating cost and repair-vs-replace calculators produce rough estimates from published average prices and general rules of thumb. They are not quotes, energy audits or professional advice. Actual costs depend on your home, climate, equipment condition and local prices.
No warranty and limitation of liability
Information is provided "as is" without warranties of any kind. To the extent permitted by law, HeatingCodes and its editor are not liable for any loss, damage or injury arising from use of, or reliance on, this website. See the terms of use.
No affiliation
HeatingCodes is independent. Carrier, Trane, American Standard, Goodman, Rinnai, Rheem, Navien, Bradford White, Mitsubishi Electric, Daikin, Honeywell Home, Lennox and other names are trademarks of their owners and are used only to identify the equipment a document covers. We are not endorsed by or affiliated with them.