York, Luxaire and Coleman furnace flash codes

York's furnace controls store the last five faults and will replay them on demand — which makes them unusually good at diagnosing an intermittent problem, and unusually easy to wipe by accident.

Also covers: Luxaire, Coleman — same manufacturer, same controls, same codes.

York, Luxaire and Coleman are the same manufacturer and share integrated furnace control boards. These boards use colour as well as count: a green heartbeat means idle, an amber heartbeat means a call for heat, and counted red flashes are faults. Their most useful feature is a stored fault history — the last five faults, replayed by pressing the LAST ERROR button on the control board.

Worth knowing before you count

The stored history is the most valuable thing these boards offer and the easiest to destroy. Holding the same button for five seconds clears the memory. If a furnace has been faulting intermittently, get the history read before anyone resets anything.

York, Luxaire and Coleman

Fault code retrieval — How to read and clear stored fault codes on York UTEC boards
Green heartbeat — Normal operation, no call for heat, no active errors
Amber heartbeat — Normal operation with a call for heat
1 red flash — Flame sensed with the gas valve off
3 red flashes — Pressure switch open, or first stage pressure switch open
3 double red flashes — Second stage pressure switch stuck open
5 red flashes — Open rollout switch
6 red flashes — Pressure switch cycle lockout
7 red flashes — One hour lockout after ignition retries
8 red flashes — Lockout on recycles, flame dropouts
9 red flashes — Grounding, reversed polarity, or reversed transformer leads
10 red flashes — Gas valve energised with no call for heat
11 red flashes — Limit switch open more than five minutes — blower failure
12 red flashes — Open hot surface igniter
Rapid red flashing — Twinning error or incorrect 24 volt phasing
Rapid amber flashing — Low flame sense current
Solid LED — Control fault detected
Steady off — No power to the board, or control failure
2 red flashes — Pressure switch stuck closed, or an inducer error
4 red flashes — Open high limit switch
3 amber flashes — Second stage heat present with no first stage call
4 amber flashes — Cooling called with no fan call
2 amber flashes — Normal operation with a call for second stage heat

Other manufacturers

This site is a reference, not a substitute for a licensed HVAC technician. Gas appliances can leak carbon monoxide and cause fire. Anything involving gas lines, the heat exchanger, or the flame sensing circuit should be handled by a licensed professional. Pages are written with AI assistance from the sources listed on each page and checked against them before publishing.