Combination boiler hot water

Hi,
A corgi registered plumber recently changed the fan in my glow worm combination boiler, because the old one was making a noise. This is now fine, but since the plumber left the hot water doesn't work properly, the boiler fires up when you turn the hot tap on, then shuts down after a few seconds, then starts up again for a few seconds etc. The water pressure seems fine, and I don't think the boiler is shutting down because it's overheating.
If I turn the heating on for a while, then turn on the hot tap, the boiler sometimes stays on heating the water.
Any ideas what this could be, I assume it's some sort of bad contact that should be simple to fix?
The original plumber has twice promised to come round to fix it and not turned up either time, and now I can't get hold of him...
Thanks
Ryan
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On 15/09/2008 09:31, Ryan wrote:

So long as you're sure the new problem started at the time the fan was replaced (rather than being a coincidental issue that started shortly afterwards) make it clear in writing to the original plumber that if they don't fix the new problem within a reasonable period of time (7 days?) you will engage someone else to repair it and then pursue the original plumber for the cost of the remedial work.
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Thanks for your post.
The guy fixed the fan in the afternoon, and when I got home in the evening the hot water wasn't working. I only had the fan replaced because it was making a high pitch squeek when warming up, there was nothing actually wrong with the boiler. Wish I hadn't bothered....
I'm not sure writing will do much good, but I'll give it a try. I haven't had hot water now for 4 days and I needed it sorted asap...
Anyone got any ideas to exactly what the problem could be?
Thanks
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On Mon, 15 Sep 2008 02:14:50 -0700, Ryan wrote:

Sounds like a new fault tome. Probably the diverter valve, especially as it works OK after you have used the heating (and thus disturbed the DV).
--
Ed Sirett - Property maintainer and registered gas fitter.
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Yeah - completely different faults
The fan is venting the combustion chamber and doesn't know whether it's for CH or DHW
Having not mentioned what boiler it is (AFAICS) there is the possibility that he could have damaged the pcb, but it's very much an outsider and extremely unlikely
--
geoff

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It's a glow worm Compact 80e fanned flue combination boiler. It looks like I'm going to have to get someone else to have a look at this then. Previous plumber has gone underground. I take your point that it is a different fault, but it is a hell of a coincenence. The least the guy could have done was check that it was working correctly before he left...
Thanks for everyones input
Ryan
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If anyone is interested, another plumber fixed the problem. It was caused by bad fitting of the flue, which was causing the boiler to switch off when running the hot water.
I still haven't got hold of the original plumber, but there isn't much point now. I would definitely not recommend City Boilers (based SW London), but seeing as though the phones aren't answered I doubt anyone will.
Ryan
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