"The Natural Philosopher" wrote in message
...
Er, no, it doen't. The fact that heat has been taken out of the water
indicates that the house has cooled enough for some TRV's to open...
Ok there is marginal loss through hot water pipes under floors etc that
set a base level of heating that the system never drops below, but I
would suggest that anyone who runs their heating at all when they don't
actually need their radiators on is a bit of a plonker.

In more normal situations, the slight heat loss through the pipework is
far more than compensated by not having UN TRV'ed radiators overheating
rooms that are not in use, or need to be set at lower temperatures.

TRV'ing everything and ruinning the whole sytem on a time clock is far
more energy efficient than having a master thermostat and no TRV's


I wasn't aware that anyone was suggesting having just a stat and no TRVs.

The *ideal* system - from an energy efficiency point of view - would have a
separate zone valve and room stat for each rad - an would be wired so that
the boiler and pump would only run when one or more zones required heat.
Better still, the room stats would be programmable - so that each room could
have a heating profile to match its likely use.

Failing that, the next best solution is:
* a timer to turn the whole lot on and off at pre-defined times
* TRVs on all but one radiator
* a room stat in the room with the non-TRV radiator (whose lockshield should
be turned down a bit to make this the last to get hot)
* an interlock which ensures that the boiler and pump both stop when the
room stat is satisifed

My understanding is that new systems would have to have all of these
features in order to satisfy the new building regs. Your solution (whilst
legal for an existing system) wouldn't comply with the new regs - because
you have no interlock which turns the boiler off when all demands are
satisfied.

Roger