Boiler not firing up? Work through these checks first
Boiler will not start and the heating is dead? Before you panic, run through these common causes and safe checks.

A boiler that will not fire up is alarming, especially in winter, but the cause is often something simple you can check yourself before calling anyone out.
Run through the basics
- Pressure. Check the gauge. Below 1.0 bar and the boiler will not fire for safety. Top it up, our pressure guide shows how.
- Power. Check the boiler has power and that a fuse or switch has not tripped.
- Gas. Is your gas supply on? Check another gas appliance, like a hob, is working.
- Thermostat and timer. Make sure the heating is actually programmed to be on and the thermostat is turned up.
- Fault code. Note any code on the display. Manufacturer sites like Worcester Bosch and Ideal explain what each code means.
Frozen condensate pipe (a winter classic)
If it is cold out and your boiler suddenly stops with a fault, a frozen condensate pipe is a common culprit. This is the white plastic pipe running outside. Gently warming it with a warm cloth or a hot water bottle often thaws it, then reset the boiler.
Try a reset
Most boilers have a reset. Hold it for a few seconds. If the boiler fires and stays on, you are sorted. If it keeps locking out, stop and call a professional.
When to call an engineer
If the basics check out and the boiler still will not fire, it is an engineer job. Whether you are with a national like British Gas or want a faster local option, Norvera matches you with a vetted Gas Safe registered engineer near you. If the boiler is old and this is one of many problems, it may be time to read our signs you need a new boiler guide. Either way, tell us what is happening.
Frequently asked questions
Why is my boiler not firing up?+
The usual causes are low pressure, a tripped fuse or switch, no gas, a frozen condensate pipe in winter, or a fault code. Many of these you can check yourself in a few minutes.
How do I reset my boiler?+
Most boilers have a reset button or dial. Hold it for a few seconds until the boiler tries to relight. If it fires up and stays on, great. If it keeps locking out, it needs an engineer.
My condensate pipe is frozen, what do I do?+
In cold weather the external condensate pipe can freeze and stop the boiler. Gently warming it with a hot (not boiling) water bottle or warm cloth often clears it, then reset the boiler.
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