Furnace flashing 6 times: what 6 flashes means
The number of flashes on a furnace control board is not a standard. Every manufacturer assigns its own meanings, and 6 flashes means something different on each of the 3 control families below.
These are not variations on one fault. They are entirely different problems, and the count alone does not distinguish them. Identify the manufacturer before acting on any of them.
6 flashes, by manufacturer
| Furnace brand | What 6 means there |
|---|---|
| Goodman Goodman GMS, GMH, GMV8, GMV9 and Amana AMH, AMV9 series | Rollout switch has tripped |
| Goodman Goodman GMSS9 and Amana AMSS9 series | Rollout limit open, or control module fuse blown |
| Trane 6 flashes | 115 volt AC power reversed, or poor grounding |
Finding out which brand you have
The brand is printed on a rating plate inside the furnace cabinet, usually on the inner wall behind the removable front panel, and often repeated on a sticker on the outside of that panel. The name on the thermostat is not reliable — thermostats are replaced far more often than furnaces, and a great many furnaces are sold under a different name from the company that built the control board. The brand hubs below list the alternative names each manufacturer sells under.
- Goodman — also Amana
- Carrier — also Bryant, Payne
- Trane — also American Standard
- Lennox
- York — also Luxaire, Coleman
- Rheem — also Ruud, Weather King
- Heil — also Tempstar, Comfortmaker, Arcoaire, KeepRite
- Armstrong — also AirEase, Concord, Ducane
If the furnace shows a number rather than flashes
Several manufacturers stopped using flash counts and display a two-digit status code or a letter-and-digit code on a seven-segment display instead. If what you are reading is a number on a small screen rather than a light going on and off, count nothing — read the code directly and look it up on the manufacturer's page.
Other flash counts
Sources
Every meaning on this page comes from the manufacturer document behind its code page:
- Goodman Manufacturing — Diagnostic Code Identification System (model-specific fault code lookup)
- Trane Installer's Guide 18-CD29D1-14-EN — Table 21, Integrated Furnace Control Error Flash Codes