Boiler overheating

11 Dec 2012
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United Kingdom
I have had plumber in re do my bathroom to put in mains shower rather than electric while away.
I got back and pressure was zero which was because hr had drained system. He was called away last minute so was part way through job. He came to finish off yesterday and it turns out he hadnt drained total system just some of the rads.

Now when he pressurised it to 1bar, the system the second it fires up it starts to over heats, the pressure flys up and when to gets over 88, boiler shuts down.

I have a greenstar 30CDI and he appears to have snapped the pressure key. I think he has done this while in the open position(as he can still top up pressure in the system)

Two questions -

1. Would this neong open account for the over heating?

2. if not and it is something else. (blockage etc) how likely it is that it is from his work rather than unfortunate timing?
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Check to see if the isolation valves below the boiler are open, if they are check to see if the pump is sticking.
Could just be air in the system preventing circulation. Get him back to sort it
He is on site now as went to get new pressure key and to remove snapped one so he can close valve. Just not sure whether to hold him accountable or not for the issue as dont know if it is his doing or a separate fault.
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Going on the assumption your boiler was fully working before then definitely an air lock. It maybe just your pump is airlocked, or maybe a coincidence and your pump has seized.
My bathroom guy couldnt sort. Had Someone else out and the pump bust. Either coincidence or the timer on heating coming on while system was partially drained caused it to fail. thanks for advice

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