On 15/08/2016 13:50, Dan S. MacAbre wrote:


Fortunately, the boiler, pump, and valves are physically close,
electrically linked through a big hole in the boiler cupboard ceiling.
So working out how it is wired shouldn't take too much time. Each
radiator does have a TRV, and I'll just have to hope that there is,
indeed, a bypass somewhere.

Interesting to know that the room stat isn't strictly necessary.

It *is* necessary to meet current regs - but wouldn't have been when
this system was installed.

Current regs require "boiler interlock" - which means that the boiler
gets turned off when there's no demand from any of the zones. If you
just have TRVs and no room stat, the boiler wastes energy by keeping
itself hot when it doesn't need to.
--
Cheers,
Roger
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