York furnace 5 red flashes: Open rollout switch
Five red flashes means a rollout switch opened. York marks it as a hard lockout rather than a one hour soft lockout, which is a deliberate distinction — this one does not release itself on a timer.
Applies to: York, Luxaire and Coleman gas furnaces using the UTEC integrated furnace control boards documented in technical service letter ST-045-09. York marks this code as a hard lockout, not a soft one.
What it means
Rollout switches sit on or near the burner assembly and open when heat appears where it should not, meaning flame escaped forward out of the burner box rather than being drawn through the heat exchanger. That indicates the combustion path is obstructed or the draft has failed, and it can produce carbon monoxide. York's table marks this code with a hard lockout notation, distinguishing it from the codes that release after an hour. That distinction is meaningful: the control is not going to retry, because retrying would put the furnace back into a condition that should not recur without someone establishing why it happened.
Most common causes
- A blocked or restricted heat exchanger.
- A blocked or partly blocked flue, forcing combustion products back toward the burners.
- A failed or weak draft inducer not pulling flame into the heat exchanger.
- A cracked heat exchanger disturbing the combustion airflow.
- Burners that are dirty, misaligned, or partly blocked.
- Insufficient combustion air in a confined furnace space.
- Overfiring, with gas pressure set too high.
How to diagnose it
- Treat this as a stop-and-call fault. Its causes are dominated by conditions that produce carbon monoxide.
- Check that carbon monoxide alarms are present and working. If any has sounded, leave and call the fire service from outside.
- Look for visible scorching, soot, or melted wire insulation near the burner compartment — from outside, without dismantling anything.
- Note whether the flue or vent termination is obviously blocked.
- Note that this is a hard lockout, so a furnace that has restarted on its own was not showing this code.
How to fix it
- Turn the furnace off at its service switch and call a licensed heating technician.
- Do not press rollout switch reset buttons to restart the furnace. The switch tripped because flame went somewhere it should not.
- Have working carbon monoxide alarms on every level of the home and outside each separate sleeping area, which is what NFPA 720 and US Consumer Product Safety Commission guidance call for. That includes the level the furnace is on — basements, attics and utility spaces are where a combustion fault starts, and an alarm only on bedroom floors can miss it for a long time. This fault is one of the situations those alarms exist for.
- Every underlying cause — heat exchanger, flue, inducer, burners, gas pressure — is licensed work.
Notes
York marking this a hard lockout while marking the ignition and pressure switch lockouts as one hour soft lockouts is the manufacturer ranking its own fault codes by seriousness. That ranking is worth trusting.
Related
- 11 red flashes — Limit open more than five minutes — blower failure
- 3 red flashes — Pressure switch open
All codes for this manufacturer
York, Luxaire and Coleman furnace flash codes — every code, with what differs between models.