HeatingCodesYork TM9V furnace 7 red flashes: ignition failure (and 8 red, continuous amber)
What 7 red flashes means
York's TM9V*C manual says: "7 red flashes: this fault code indicates that the flame could not be established during three trials for ignition. Check that the gas valve switch is in the ON position. Check for low or no gas pressure, a faulty gas valve, a dirty or faulty flame sensor, a faulty hot surface igniter, loose wires, or a burner problem. The furnace locks out for 1 h and then restarts."
The first item, the gas valve switch, is one of the few things a homeowner might confirm, but only by looking. It is on the gas valve inside the furnace, so do not remove panels unless you are qualified.
Flame-related codes on this furnace
| LED | Meaning (per York) |
|---|---|
| Continuous amber | Flame sense current is below 1.5 microamps. Check and clean the flame sensor and check gas flow. Normal flame sense current is about 3.7 microamps DC. The low flame warning starts at 1.5 microamps, and the lockout point is 0.1 microamps. |
| 1 red | Flame was sensed when there was no call for heat. The control turns on the inducer and blower. Check for a leaking or slow-closing gas valve. |
| 7 red | Flame could not be established in three ignition trials. 1-hour lockout, then restarts. |
| 8 red | Flame lost five times (four recycles) during the heating cycle. Check for low gas pressure, a dirty or faulty flame sensor or a faulty gas valve. 1-hour lockout, then restarts. |
| 10 red | Gas valve energized with no call for heat. Check the gas valve and its wiring. |
The flame sensor numbers come straight from the manual. They are useful for a technician with a meter, not for a homeowner. If 1 red or 10 red flashes appear, treat them as a safety fault and call for service.
Soft lockout explained
York says the control has a soft lockout that resets automatically after 1 hour, which "provides protection to an unoccupied structure if a temporary condition exists causing a furnace malfunction." An example is a temporary gas interruption that prevents the furnace from lighting. The control keeps trying each hour and resumes normal operation if the gas supply is restored. A hard lockout is different: it needs power to the control turned off and back on.
Safe homeowner checks for York furnace 7 red flashes
- Check that gas is on to the houseSee whether another gas appliance works. If you smell gas, leave the house and call your gas utility from outside.
- Clear outdoor vent and intakeClear snow or ice from the vent and combustion air terminations from the ground. Do not remove pipes.
- Wait for the automatic restart or cycle powerYork says the furnace restarts after 1 hour. You can also turn power off at the switch for a moment and back on.
- Call a technician if it repeatsIf 7 red flashes returns, call a heating technician. Gas pressure, igniter and flame sensor checks need tools.
Frequently asked questions
How long does a York 7 red flash lockout last?
York says the furnace locks out for 1 hour and then restarts.
Is a dirty flame sensor a common cause?
It is one of the causes York lists, along with gas problems, a faulty igniter and burner problems. Do not assume it is the only cause.
What is the flame sensor current test?
York lists normal flame sense current as about 3.7 microamps DC and says to verify current is greater than 1.5 microamps at the test pad. That requires a meter and is for technicians.
Sources
- Installation Manual 5750149-UIM-I-0423: Two-Stage Variable Speed ECM Residential Gas Furnaces, TM9V*C series (96% AFUE), Furnace control diagnostics (Johnson Controls (York)) Covers: York TM9V*C two-stage variable-speed 96% furnaces. Other York and Coleman furnace series use different boards and flash codes; check the label on your furnace.
Safety note: this page is general information drawn from the sources above. Gas, combustion and line-voltage repairs belong to a licensed professional. Your own equipment's label and manual take priority over anything here. Read the full disclaimer.