York furnace 12 red flashes: Open hot surface igniter
Twelve red flashes means the hot surface igniter circuit is open. A hot surface igniter fails by cracking, and a cracked igniter is electrically open.
Applies to: York, Luxaire and Coleman gas furnaces using the UTEC integrated furnace control boards documented in technical service letter ST-045-09.
What it means
A hot surface igniter is a ceramic element that glows red hot to light the gas, and it is a consumable part — it fails eventually on every furnace that uses one. It fails by cracking, and a cracked igniter reads as an open circuit, which is exactly what this code reports. That makes it one of the more straightforward furnace faults: the diagnosis is usually confirmed by measurement and the remedy is replacement. Because the igniter sits in the burner compartment and is fragile, it is also a part that can be broken during other service work.
Most common causes
- A cracked or failed hot surface igniter, which is the usual cause.
- Igniter wiring disconnected, loose, or damaged.
- A connector at the igniter not seated.
- An igniter at the end of its service life.
- Damage during previous service work, since igniters break easily when handled.
- A failed igniter output on the control board.
How to diagnose it
- Note whether the igniter glows at all during a start attempt, if the furnace has a sight glass. An igniter that never glows fits this code.
- Note whether the furnace has been serviced recently, since igniters are fragile.
- Note the age of the furnace and when the igniter was last replaced, since these are wear parts.
- Do not attempt to inspect or measure the igniter — it is inside the burner compartment.
How to fix it
- This is technician work in the burner compartment and ignition circuit.
- A replacement igniter should be the correct part for the model, since these differ.
- Ask for the connector and wiring to be checked as well, since a disconnected lead produces the same open circuit as a broken element.
- Expect this to be one of the more affordable furnace repairs and one of the more common.
Notes
A furnace more than a decade old that has never had its igniter replaced is due. This code is often the furnace reaching an ordinary maintenance point rather than developing a fault.
Related
- 7 red flashes — One hour lockout after ignition retries
- 9 red flashes — Grounding, reversed polarity, or reversed transformer leads
All codes for this manufacturer
York, Luxaire and Coleman furnace flash codes — every code, with what differs between models.