The reset button is there for one controlled restart after a lockout. It is not a way to force a faulty burner to keep running.

Key points

  • Check oil, power and controls first.
  • Reset once only if there are no unsafe signs.
  • Repeated lockout means the boiler needs diagnosis.
  • Smell, smoke, leaks or unusual noise mean stop.

Before pressing reset

Check the oil level, programmer, thermostat, fused spur and any obvious switches. Make sure the boiler is being asked to run.

Look and smell around the appliance. If there is oil smell, smoke, a leak or unusual noise, do not reset it.

One reset only

If everything looks normal, one reset may allow the burner to restart after a simple interruption. Watch and listen from a safe position.

If it locks out again, leave it off. Pressing reset repeatedly can put unburnt oil into the chamber and make the fault more serious.

Why lockouts happen

Lockouts can be caused by oil supply restriction, ignition failure, photocell faults, blocked nozzles, poor combustion, control faults or a failed component.

The lockout is the boiler protecting itself and the property from unsafe operation.

What to tell the engineer

Useful information includes the boiler make, what lights are showing, whether the burner tries to start, whether there is a smell, and how many times it has locked out.

Photos of the boiler data badge and control panel can also help before a visit.

Common questions

How many times can I reset an oil boiler?

As a general safety rule, once. If it locks out again, stop and get the fault checked.

Why does it run after reset then fail again?

The burner may be able to start briefly but still have an underlying oil supply, ignition, flame detection or combustion fault.