Combi boiler producing no hot water

🔒 Written by a Gas Safe registered engineer
May Need Pro💷 £0£2505–10 min
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Safety First
⚠️ If you smell gas, leave the property and call 0800 111 999.

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Most likely cause & what to check

1

Check the boiler pressure gauge on the front of the boiler — it should read between 1 and 1.5 bar. If it's below 1, the boiler won't heat your water. Use the filling loop underneath to top it up, then press the reset button.

Step 1 illustration
2

Check your programmer or thermostat hasn't accidentally been set to heating-only. Make sure hot water is switched on.

Step 2 illustration
3

Look at the boiler display for any fault codes — take a photo and use our Boiler Fault Code tool to find out what it means.

4

If those checks don't fix it, call a Gas Safe engineer. Tell them: "My combi boiler isn't producing hot water — heating may still be working. I've checked the pressure and programmer."

🛠 Tools & materials you may need

Boiler manual
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