Heating Solutions for Professionals
Are you a Homeowner?
Switch to Homeowners Site

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.

Couldn't find what you were looking for?

Alternatively you can speak to a member of our team - Subject to Operating Times

+44 (0)1380 736920 info@grantuk.com

Return to top