HVACopediaYork · Furnace
LED steady off Board LED dark - no power to control
What the control is telling you
The diagnostic LED shows nothing at all. The control is not powered, its on-board fuse has opened, or the board itself has failed. Older White-Rodgers boards may still hold fault codes even with a blown fuse.
Applies to: York/JCI residential gas furnaces: York UTEC IFC furnaces, York White-Rodgers IFC furnaces, York TM9V
Likely causes
- No 115 V supply (breaker, service switch, blower door switch)
- Blown 3 A ATO fuse on the board from a 24 V short
- Failed transformer
- Failed control board
Test and repair steps
- Warning: Line voltage is present inside the cabinet - work carefully.
- Confirm 115 V at the furnace and that the blower door switch is pushed in.
- Check 24 V at the transformer secondary.
- Inspect the 3 A automotive-style fuse on the board; if open, find the low-voltage short (thermostat wire, outdoor unit wiring) before replacing it.
- If power and fuse are good but the LED stays dark, replace the control board.
Settings for these units
Clearance to combustibles · York TM9V
| Side of furnace | Upflow | Downflow | Horizontal |
|---|---|---|---|
| Top / vent / rear / side / front | ? | ? | ? |
| Combustible floor | Yes | Yes (special sub-base only) | Yes |
| Closet | Yes | Yes | Yes |
| Line contact | No | No | Yes |
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
| Airflow | Cabinet | Side return filter | Bottom return filter |
|---|---|---|---|
| 1000 CFM | A | 16 x 25 in. | 14 x 25 in. |
| 1200 CFM | B | 16 x 25 in. | 16 x 25 in. |
| 1600 CFM | C | 16 x 25 in. | 20 x 25 in. |
| 2000 CFM | C | (2) 16 x 25 in. | 20 x 25 in. |
| 2000 CFM | D | (2) 16 x 25 in. | 22 x 25 in. |
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
- 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
- 12 red flashes Hot surface igniter open / igniter failure
- 13 red flashes High-fire pressure switch open
- Rapid amber flash Weak flame signal
- Rapid red flash Twinning error or wrong 24 V phasing
- Steady on (any color) LED lit solid - internal control fault
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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; York TM9V - -M9V 96% two-stage variable speed installation 1083294-UIM-A-0114.pdf - section Furnace Control Diagnostics. 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.