York · Furnace

12 red flashes Hot surface igniter open / igniter failure

High severity York UTEC IFC furnacesYork White-Rodgers IFC furnaces

What the control is telling you

The board detects an open or failed hot surface igniter circuit.

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

Likely causes

Burnt or cracked igniter
Broken igniter wiring or plug
Board igniter relay

Test and repair steps

Check igniter resistance with power off; open circuit means replace.
Check the igniter plug and wires.
Check for 115 V to the igniter at warm-up; if missing, replace the board.
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
Filter size by return location · York TM9V

Other codes on the same units

7 red flashes Ignition failure lockout (retries)
8 red flashes Flame lost repeatedly (recycles)
9 red flashes Polarity reversed or bad ground
10 red flashes Gas valve powered with no heat call
11 red flashes Limit open 5-15 minutes - blower failure
LED steady off Board LED dark - no power to control
Rapid amber flash Weak flame signal
Rapid red flash Twinning error or wrong 24 V phasing

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Source: York All JCI single-two-stage furnaces with UTEC IFC board codes ST-045-09.pdf - section Fault Code LED Flashes; York JCI single-two-stage furnaces with White-Rodgers-Emerson IFC (older installed base) codes ST-028-07.pdf - section Fault Code Sheets. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.