Furnace gas valve fault codes by manufacturer
Gas valve codes are the shortest list on this site and the one where the advice is most consistent: stop and call a technician.
What the gas valve does
The gas valve is the electrically operated valve that admits gas to the burners. On most modern furnaces it is a redundant valve — two valve seats in one body, in series — so a single failed seat cannot pass gas on its own. The control energises it only after the inducer has proved draft and the igniter has completed its warm-up.
Why one part produces several different codes
Manufacturers report gas valve faults in two ways: a circuit fault, where the control did not see the valve respond as commanded, and a flame-sensed-with-valve-closed condition, which implies the valve may be passing gas when it should be shut. On some ICP equipment the diagnostic codes come from the valve itself rather than the control board, which is why two ICP documents give different meanings for the same flash count.
Every gas valve code on this site
9 codes across 6 control families. The meaning is the manufacturer's, from the document listed at the foot of each code page.
| Brand | Code | What it reports |
|---|---|---|
| Armstrong | 12 flashes | Flame sensed without the gas valve energised |
| Carrier | Status code 22 | Abnormal flame-proving signal — flame detected with the gas valve closed |
| Goodman | solid red | Internal control fault, gas valve error, microprocessor or frequency check failure |
| Lennox | Alert code 204 | Check gas valve |
| Lennox | Alert code 205 | Gas valve relay contact closed |
| Lennox | Alert code 206 | Gas valve second stage relay fault |
| Trane | 7 flashes | Gas valve circuit error |
| York | 1 red flash | Flame sensed with the gas valve off |
| York | 10 red flashes | Gas valve energised with no call for heat |
Before you work on it
Every fault on this page involves the component that controls gas flow. None of them is homeowner-serviceable. If there is any smell of gas, leave the building first and call the gas utility from outside.
Other parts
- Furnace pressure switch codes on every brand
- Furnace high limit switch codes by brand
- Furnace flame sensor codes on every brand
- Furnace rollout switch codes: why it tripped
- Furnace igniter fault codes by manufacturer
- Furnace inducer motor fault codes by brand
- Furnace grounding and reversed polarity codes
Sources
Every code meaning above comes from the manufacturer document behind its code page:
- Allied Air Enterprises — A80UH1E and 80G1UHE Installation Instructions 507330-03, Table 7: Diagnostic Codes for -02 Control
- Carrier 58MCB Service Manual, 327884-101 Rev. B — status codes
- Goodman Manufacturing — Diagnostic Code Identification System (model-specific fault code lookup)
- Lennox Residential Communicating Systems Alert Code Guide, document 100017, March 2023 — Table 2, Alert Codes and Troubleshooting
- Trane Installer's Guide 18-CD29D1-14-EN — Table 21, Integrated Furnace Control Error Flash Codes
- Johnson Controls Unitary Products technical service letter ST-045-09 — York UTEC furnace boards, fault code tables and retrieval procedure