1 red flash Flame detected with gas valve off

What the control is telling you

Flame is seen when there should be none. The board runs the inducer and the main blower to clear the heat.

Applies to: York/JCI residential gas furnaces: York UTEC IFC furnaces, York White-Rodgers IFC furnaces, York TM9V

Likely causes

• Gas valve leaking through or closing slowly
• Flame sensor circuit fault

Test and repair steps

1. Warning: Shut off gas at the manual valve if flame remains after the call ends.
2. Watch the burners after the thermostat is satisfied - any flame means the valve is passing gas.
3. Replace a leaking or slow-closing gas valve.
4. Check the flame sensor wiring for shorts.
5. To read stored codes with no thermostat call active, tap the LAST ERROR button briefly (under 5 s); up to five codes play back newest first. Two green flashes = memory empty. Hold the button 5 s or more to clear (three green flashes confirm).

Settings for these units

Clearance to combustibles · York TM9V

Leave about 24 in. at the front and 18 in. at the side for service.

Approved for alcove and attic installs.

Filter size by return location · York TM9V

Sizes assume high velocity filters (600 FPM); throwaway filters must stay at or below 300 FPM.

Filters go outside the cabinet - never inside the furnace.

Models that show this code

7 models in York UTEC IFC furnaces, York White-Rodgers IFC furnaces, York TM9V

Other codes on the same units

• 2 red flashes Pressure switch closed when it should be open
• 3 amber flashes W2 call without W1
• 3 double red flashes Second-stage pressure switch not closing
• 3 red flashes Pressure switch open when it should be closed
• 4 amber flashes Cooling call (Y) without fan call (G)
• 4 red flashes Main limit switch open
• 5 red flashes Rollout switch open / limit circuit open over 15 min
• 6 red flashes Pressure switch cycling lockout