Boiler heating up but not getting through to central heating or hot water

30 Mar 2021
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United Kingdom
A bit puzzled at the moment.
I removed a section of central heating pipe that had a screw put through it.
Since then we have had no hot water or central heating. To solve the issue so far I have done the following:
- Bled all the radiators (alot of air released from those near the fixed pipe bit now all radiators are running water through them - but not hot)
- Drained the boiler at the release valve to see if any air was trapped.
- Turned up boiler and heating to full.
- checked diverter valves and they are working as normal.

Also took to front off boiler and at the source it is heating water (pipe hot to touch) but a few feet down the pipe it is only warm and then a few feet more it is not warm at all.

Anything else I can try.

Thanks on advance

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Hello Kev,

what type of setup? Ie; Combi boiler, system boiler, heat only? Controls?
As above, do you have header tanks and a hot water cylinder?
Is the pump running when the controller is calling for heat?
Set up attached.
I have reset my nest panel and hot water is now leaving the boiler but not making it to the diverter valve pipes.


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Sounds like there’s still trapped air, possibly at the pump, and the makeshift air vent (the drain off pointing upwards) at the cylinder. There‘s a possibility that removing the cover on that boiler requires checking for safety afterwards too.
When you say 'diverter' valves presumably you mean the motorised valves in pic 2?
Is the pump running? Are the valves operating?
Unbelievably, it was just the reseting of the nest controller that got it working. There's a day I will never get back.

Thanks for the suggestions

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