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Overheating valliant VCW Sine 18 combi

Postby Dabs » Mon Nov 24, 2008 3:13 pm

The overheat reset on my valliant VCW Sine 18 keeps kicking in.

The heating works fine but as soon as I turn on hot tap the overheat reset kicks in almost immediately, no hot water delivered at all.

Had several plumbers come around and they all say 'could be this could be that, best to get a new boiler'. A couple said they can try changing some parts but can't guarantee the work as it's so old.

(Had the whole system power flused about 6 months ago, after which the host water was working fine but was very very hot for about the 1st 15 seconds or so before stabalising. Plumber said 'It would be ok after some use'? Has never really got back to normal since but at least I had hot water then, now overheat just kicks in.

Anybody any ideas what it may be?
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Simply Build It

Postby htg engineer » Tue Nov 25, 2008 12:11 pm

Get a RGI - it could be as simple as the gas pressures are set too high, faulty overheat stat, or a blockage in the plate heat-ex.

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