Boiler programmer or timer not working

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DIY Friendly💷 £0£8020–45 min

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Most likely cause & what to check

1

Check the programmer display is showing the correct time — a power cut will reset the clock on older programmers.

2

Check the programme settings: ensure heating is set to ON for the current time period, not TIMED or OFF.

3

For battery-powered programmers: replace the batteries.

4

Try running the heating in CONSTANT/OVERRIDE mode to check whether the boiler itself is working — if it fires up, the programmer settings are the issue.

5

Check all wiring connections at the back of the programmer are secure.

6

If the programmer display has gone blank or is showing errors, it may need replacing. Most are plug-and-play replacements and don't need an engineer.

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