In article ,
The Natural Philosopher wrote:
With a TRV system, the idea is to pump more or less continuously, and
let the TRV's decide on demand. The boiler merely cuts in when the
return flow has dropped to the boiler stat level.

Use of TRV's with an overall zone stat makes them essentially useless.
Either they are still demanding heat when the main stat cuts out, or
they have shutdown before it itself does, in which case it never
does.... you cannot have a romm or area controlled by two stats on
essentally the same zone.

Fine if you want the same temperature all the time the heating is on, but
most don't.

I have a programmable stat in the living room which has no TRVs. Every
other rad has. The house comes up to the morning temp set by a combination
of the room stat and TRVs - obviously the room with the stat mustn't be
the first to reach its set temperature - and when the later daytime lower
temp switches in the whole house drops pretty consistently, and maintains
that new temperature. Similarly with the higher evening temperature - and
much lower nighttime one if I leave it on 24 hours as I do in very cold
weather.

It's called balancing the system. ;-)

--
*A fine is a tax for doing wrong. A tax is a fine for doing well.

Dave Plowman London SW 12
RIP Acorn