Boiler & Heating Breakdowns

Check these three things before anything else

Look at the pressure gauge on the front. With the heating cold, most combi boilers want roughly 1 to 1.5 bar. Somewhere around 0.5 bar or lower, most lock out on purpose, which is covered in why boiler pressure keeps dropping.

Next, the display. Write down any code before you press reset, then press it once only. A reset clears the screen, not the cause, and some boilers stop accepting resets after a few attempts. If you have a code, the fault codes by brand section explains it.

In a cold snap, check the white or grey plastic condensate pipe where it leaves the wall outside. A frozen one stops a condensing boiler firing. Pouring warm, not boiling, water along it is a safe householder fix.

If you smell gas, open windows, turn off the gas at the meter if you can reach it safely, do not use light switches, then leave and call the National Gas Emergency Service on 0800 111 999. Nothing inside the boiler casing is a DIY job.

Boiler leaking or losing pressure

First find where the water comes from. A drip from the short copper pipe that runs from the boiler through the outside wall is usually the pressure relief valve letting off excess pressure, which still needs looking at, see relief valve leaking. A leak from inside the casing is an engineer job, and is a leaking boiler dangerous explains when to switch it off at the fused spur.

Pressure that falls every day with no visible water usually means a slow leak under a floor or a failing expansion vessel. Topping up keeps you warm for a night, it does not fix anything.

Boiler will not fire, keeps turning off or makes noise

An ignition lockout means the boiler tried to light several times and gave up. Start with boiler not firing up: gas to the hob, prepayment meter credit and the condensate pipe come first.

Banging, kettling and whistling usually point to limescale on the heat exchanger, a sticking pump or air in the system. Our guide to a boiler making a loud noise sorts the harmless sounds from the ones that need the boiler off now.

If the boiler runs but one room stays cold, the fault is often in the radiator, not the boiler. Work through radiator not heating up in order before calling anyone.

When it cannot wait until morning

Water coming from inside the casing, a burning smell, sooty marks around the case or a boiler that trips the electrics all mean switch off and get help. A carbon monoxide alarm means open windows, turn the boiler off, get everyone outside and call 0800 111 999 first, then get medical advice. No heat in freezing weather is urgent too when there is a baby, an elderly person or someone unwell in the house.

An emergency boiler repair visit is the £60 call-out at any hour, and the repair price is agreed with you on site before any work starts. Gas work is carried out by Gas Safe registered engineers.