What to check if a boiler will not start?

If an oil boiler will not start, a heating engineer can check the following. Please note, it is important to always isolate the electricity supply to the boiler before working on the boiler.

1. No fuel supply

• Ensure that an adequate supply of fuel is available and that the fuel
  supply valve is open.
• Check the condition of the fuel filter and clean if necessary.
• Ensure the fuel supply is reaching the burner and vent pump.
• Check that the fire valve has not operated to shut off the oil supply.

2. No electricity supply

• Ensure electricity supply to the boiler is switched on and that all controls
  are calling for heat.
• Ensure that the overheat thermostat has not tripped and reset if necessary.
• Check that a mains supply is present at the burner terminal block.
• If not, check the boiler and overheat thermostat.

3. Burner not starting (fuel and electricity supplies present)

• Press the reset button on the burner control box if it is lit.
• Refer to burner fault finding charts provided in the Manual and follow the steps provided. 

4. Burner lights but goes to lock-out

• If the flame is unstable, check the combustion settings.
• Refer to burner fault finding charts provided in the Manual and follow the steps provided.