Ideal ES35 Combi domestic Dual Zone, CM907 Stats

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It seems that the boiler is fired only on the temperature of the water in the pipes. And the pump just keeps going !

Indeed as I said earlier that would be expected.......

With the motorised valves closed, because no hot water is being circulated around the radiators, no heat will be being lost, the boiler will reach its operating temperature and shut its burner down, meanwhile the pump will continue.

So I can't think why anyone would take out the stats and return it to the way the boiler was when it was delivered - any ideas ?

The stats haven't been taken out. The stats should not be connected directly to the boiler. You have a dual zone system, so the stats operate the motorised valves and then motorised valves should operate the boiler via their internal switches.

I can only suggest, why it may have been done, perhaps because of a faulty switch and either:
a) The fault was intermittent and so the problem may reoccur or
b) The faulty valve has since been replaced

Others may have other suggestions.