Oil boiler not firing up: a simple checklist

When an oil boiler won't fire, it is often something simple you can check before calling out an engineer. Work through this checklist first. If it still won't run, our OFTEC engineers cover East Lothian, Midlothian and the Borders.

Fuel and supply

Check the tank has oil, the supply valve is open and there is no obvious leak or water in the fuel. In cold snaps, waxing or a frozen supply line can also stop the boiler firing.

Power and controls

Make sure the boiler has power, the switch is on, and the thermostat and timer are calling for heat. Reset any tripped fuse or RCD at the consumer unit.

One reset, then call

Press the reset once. If it fires and stays on, great. If it locks out again, stop and book an engineer, as the cause is likely a nozzle, photocell or pump fault.