LAST ERROR button Read or clear the stored fault codes

What the display is showing

The board keeps up to five fault codes, newest first, even after power loss. Solid-LED errors are not stored. Retrieval only works when no thermostat signal is active.

Applies to: York IFC boards with LAST ERROR button

What to do

1. End any heating, cooling or continuous-fan call first.
2. Press and release LAST ERROR (more than 1/5 s, under 5 s). The LED flashes the stored codes starting with the most recent, with a 2 second pause between them.
3. TM9V: after the codes it returns to slow green flash after a 5 second pause. Press again to repeat.
4. Two green flashes = nothing stored.
5. To clear, hold the button 5 seconds or more; 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

• 12 red flashes Hot surface igniter open / igniter failure
• 13 red flashes High-fire pressure switch open
• Amber heartbeat Normal - call for heat, first stage on
• Green heartbeat Idle - no call for heat
• 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
• Slow amber flash Normal - call for heat