central heating gone very wierd


recently i've had a couple of radiators added to my system and a shower. everything has been running just fine for the past three weeks until last night ...
i was decorating so not paying much attention but did notice that it was very hot. i turned down the thermastat that's in the dining room several times thinking surely the radiators must turn off soon.
anyway, it wasn't until later i actually did some testing and realised that the radiators were actually coming on with the hot water heating and to make matters worse the hot water heating wasn't stopping unless i switched it off i.e. the water was definitely hot enough (in fact scalding) but the boiler was still continuously on.
i've also noticed in the airing cupboard that there's a definite continuous click click click coming from it.
to recap, the radiators are coming on and extremely hot when i turn the hot water heating on regardless of any setting that the thermostat in the dining room is. the hot water is extremely hot. there's a regular clicking sound coming from the airing cupboard about once every second.
any ideas what's causing this?
tia, alex
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Could be the control power is interrupted causing reset to the full open default. In any case, you should call a professional immediately. A runaway boiler has tremendous destructive potential.
MM
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the thermostat wires have been switched by accident.

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that
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sound
Sounds rather like the three port valve playing up to me. Can you identify where the clicking noise is coming from?
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