Boiler keeps switching itself off
Check the steps below first — if you're not confident, get it fixed safely today.
Post a job — we'll find you an engineer →⚠️ Do not repeatedly reset a boiler that keeps locking out — especially if it shows a gas or flame fault.
A boiler that fires up then cuts out after a few minutes is one of the most common heating problems we see, and the good news is that it's often fixable without calling an engineer. This typically happens when your boiler's safety systems detect something isn't quite right — usually low pressure, a fault with the ignition or flame, or occasionally a problem with the pump or thermostat. It affects countless UK homes, particularly as boilers age or after periods of heavy use during winter. This guide walks you through the most straightforward checks you can do yourself, starting with the pressure gauge, then identifying any fault codes your boiler's displaying. Most of these issues are straightforward to diagnose, though if you spot a gas fault or the boiler keeps locking out after a reset, it's important to stop troubleshooting and contact a Gas Safe registered engineer straight away.
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Most likely cause & what to check
Check the boiler pressure gauge — it needs to be between 1 and 1.5 bar. If it's below 1, use the filling loop under the boiler to top it up, then press reset.
Check the display for a fault code — note it down and use our Boiler Fault Code tool to find out what it means.
If the boiler starts then cuts out again, do not keep resetting it. Call a Gas Safe engineer and tell them: "My boiler fires up but switches itself off after a few minutes" and give them the fault code.
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Frequently asked questions
Why does my boiler keep shutting down after just a few minutes?
Your boiler has built-in safety devices that shut it down if they detect low pressure, a flame failure, or other faults. The most common culprit is pressure dropping below 1 bar, which you can usually fix yourself using the filling loop. If pressure is fine, the boiler's likely picking up a fault code that needs investigating by a Gas Safe engineer.
Is it dangerous to keep pressing the reset button on my boiler?
Repeatedly resetting a boiler that won't stay lit is not a good idea, especially if it's showing a gas or flame fault — you could be masking a genuine safety problem. Reset it once, note any fault code, and if it cuts out again, stop and call a Gas Safe engineer rather than keep trying.
How do I know if my boiler pressure is too low?
Look at the pressure gauge on the front of your boiler — it should sit between 1 and 1.5 bar when the heating is off and cold. If the needle is below 1 bar, you've likely lost pressure and need to use the filling loop (a small flexible hose under the boiler) to top it up gradually until it reaches around 1.2 bar.
What does a boiler fault code mean and how do I find out what mine is?
Fault codes are your boiler's way of telling you what's wrong — they usually appear on the display screen as a number or letter combination. Write down the exact code and use our Boiler Fault Code tool to translate it, or pass it straight to a Gas Safe engineer so they can diagnose the issue quickly and accurately.
Can low boiler pressure cause the heating to cut out?
Yes — low pressure is one of the most common reasons a boiler fires up then shuts down. Once pressure drops below about 0.8 bar, most boilers will lock out as a safety measure, so topping up the pressure using the filling loop often solves the problem completely.
Should I bleed my boiler if it keeps switching off?
Bleeding air from the system can help if the boiler won't fire up at all, but if it's firing then cutting out, low pressure is the more likely issue. Start by checking and raising the pressure first; if that doesn't solve it, a Gas Safe engineer can advise whether bleeding is needed.