Boiler Not Firing Up? 7 Things to Check Before You Call an Engineer
Pressure too low, frozen condensate, tripped RCD — the quick checks that fix most no-heat call-outs in winter without paying for a visit.
A boiler that won't fire is alarming, especially in January. The good news: roughly half the no-heat call-outs we attend in winter could have been fixed in five minutes by the homeowner. Here are the seven safe checks to run before you pay for a visit. None of these involve touching gas components — that's illegal and dangerous unless you're Gas Safe registered.
1. Check the pressure gauge
Most modern combis lock out below 0.5 bar. The needle should sit between 1.0 and 1.5 bar when the system is cold. If it's lower, find the silver flexible filling loop under the boiler, open both taps a quarter-turn until the gauge reads 1.2 bar, then close them again. Reset the boiler. About 30% of winter call-outs are this and nothing else.
2. Check for a frozen condensate pipe
If your fault code is something like EA, F1 or A04 and the weather has been below freezing, the white plastic pipe running outside (usually to a drain) has likely frozen. Pour warm — not boiling — water along the pipe, especially over any bends or the open end. Reset the boiler and it should fire within minutes.
3. Check the thermostat batteries
Wireless room stats run on AA batteries that quietly die every 18–24 months. If the screen is blank or shows a low-battery icon, the boiler simply isn't getting a 'call for heat'. Replace the batteries before you assume anything is wrong with the boiler itself.
4. Check the programmer/timer is on
After a power cut, some programmers reset to 'off' or to factory schedule. Make sure heating is set to 'on' or 'constant' and the time is correct.
5. Check the RCD/consumer unit
A tripped breaker can cut power to the boiler without affecting other circuits. Find your consumer unit and look for any switches that have flipped down — reset and test.
6. Check the gas supply
Has someone turned off the gas isolation valve under the boiler? Is the meter showing a credit if you're on a prepay tariff? Does the gas hob still work? If only the boiler has no gas and the hob does, that's a job for an engineer.
7. Try one reset — and only one
Press and hold the reset button for 5 seconds. If the boiler fires and runs normally, great. If the same fault returns within an hour, do not keep resetting — there's a real fault and repeated resets can damage components. Call us on 01257 781481.
If you can smell gas at any point, leave the property and call the National Gas Emergency Service on 0800 111 999. For everything else, our engineers handle boiler repairs in Chorley, Preston and Leyland with same-day visits whenever possible.