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.

Find Technical Specifications

Download product brochures, data sheets and installation manuals for all of Grant's oil boilers and renewable technologies.

Find technical specs

Home Heating Blog

Discover more about home heating solutions, care and support with our informative blogs

Read more

Couldn't find what you were looking for?

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

Return to top
Are you a homeowner? Please click here.