Carrier furnace Status code 22: Abnormal flame-proving signal — flame detected with the gas valve closed
Code 22 means flame is being proved while the gas valve is de-energised. The inducer runs continuously until the fault clears, and Carrier's documented causes are both about the gas valve.
Applies to: Carrier 58MCB four-way multipoise condensing gas furnaces and related models using the same integrated furnace control. Bryant and Payne furnaces of the same generation use the same control and code set.
What it means
The control monitors the flame sensor continuously, including when the gas valve is closed. Detecting flame at that point means gas is burning when none should be flowing. Carrier's response is to run the inducer until the fault clears, which pulls combustion products and any unburned gas out of the heat exchanger and up the flue. The two causes Carrier documents are a leaky gas valve and a stuck-open gas valve — both meaning gas is entering the combustion chamber outside a controlled cycle. That is why the inducer running continuously with no heat is the visible symptom of this code.
Most common causes
- A leaky gas valve, allowing gas through when it should be closed.
- A stuck-open gas valve.
- A short in the flame sensor circuit producing a false flame signal, which presents identically to the control.
- A slow-closing valve leaving flame briefly after shutdown.
How to diagnose it
- Note whether the inducer is running continuously with no heat. That behaviour accompanies this code and is the control purging the heat exchanger.
- Do not open the burner compartment while the furnace is powered.
- Note any smell of gas — if there is one, act on the fix below immediately rather than continuing.
- Read the code carefully. Two short flashes and two long flashes is 22; miscounting sends this somewhere much less urgent.
How to fix it
- If you smell gas: leave the building, operate no electrical switches, and call your gas utility's emergency line or the fire service from outside. Do not return to investigate.
- With no gas smell, switch the furnace off at its service switch and leave it off until a licensed technician has seen it.
- This is entirely technician work. Both documented causes are gas valve faults.
- Do not reset repeatedly to see whether it clears. If the valve is passing gas, each reset is another opportunity for it to accumulate.
Notes
The continuously running inducer is worth recognising as a symptom in its own right. A furnace that blows cold air out of the flue and never heats is often assumed to be simply broken; on these controls it can be the furnace actively clearing gas from the heat exchanger.
Related
- Status code 21 — Gas heating lockout — will not reset automatically
- Status code 34 — Ignition proving failure
All codes for this manufacturer
Carrier, Bryant and Payne furnace status codes — every code, with what differs between models.
Do it yourself or call a technician?
This is the code where the correct homeowner action is subtraction. Both documented causes are a gas valve passing gas while de-energised: with a gas smell that is an emergency handled from outside the building, and without one it is still a furnace to switch off at its service switch and leave off. There is no filter, drain, or reset that addresses this fault — every reset is another opportunity for gas to accumulate against a valve that may not be sealing. The one genuinely useful homeowner contribution is observational, made from across the room: confirm the inducer is running continuously with no heat. Reporting that behaviour tells the technician the control is actively purging the heat exchanger, which both confirms the code and shows the control side is doing its job.
The same fault on other brands
Flame proved while the gas valve is closed has a direct twin in most code tables: Goodman's 5 flashes, the shared Goodman GMEC96 / York UTEC board lineage's 1 red flash (York's version is nearly word for word), Trane's 5 flashes, Allied's 12, Lennox alert 241 — the flame sensor codes hub counts 22 related codes across 11 families. The same board lineage also has an earlier-warning variant, gas flow detected with no call for heat. What Carrier documents that most do not is the response: the inducer runs until the fault clears, purging the heat exchanger. Valve-side equivalents are collected on the gas valve codes hub.
What the fix costs
Both documented causes end at the gas valve, which the repair cost guide prices at $300–900 installed and labels never a DIY part — the spread is brand parts availability and how much of the gas train has to come apart to fit it. If diagnosis instead finds a false flame signal from a shorted sensing circuit, which presents identically to the control, the bill is the $75–150 diagnostic (usually credited) plus a wiring repair rather than a valve. Either way, this is one code where paying for the visit is the correct outcome even in the best case: a furnace that reported flame with the valve closed has earned a professional test of its gas train before it runs again.
What this looks like
From the outside, this usually shows up as the furnace turns over but never lights — that walkthrough covers what to check in order, and when it stops being a homeowner job.