"Lobster" wrote in message
...
andrewpreece wrote:

What valves do you have at present? It is in the regs that all new CH
installations should have a thermostat in the loop. If your
radiators have all got TRV's ( thermo- static radiator valves ) on
them, one ( typically in the hallway ) will have to have the TRV
removed, so the thermostat ( also in the same room ) can control the
CH sytem without fighting a TRV.

When you say a thermostat, aree you sayiny it is compulsory to have to
have roomstat in the one room which is not covered by a TRV? I'm about
to have a system installed and was intending to go for a towel rail in
the bathroom with manual valves, and no roomstats (all other rads with
TRVs) - does this design not cut the Part L mustard? Had a look at the
approved doc but can't find this.

Thanks
David

I'm not sure of the source, but when I installed my own boiler I was
surprised
to find out that for new installations ( post 2001 I think ) all CH systems
had to
be controlled by a thermostat in a room. The reason is that the thermostat
actually turns the boiler off instead of letting it mess around occasionally
heating up the loop water and circulating it through the bypass valve, when
all the TRV's are off because the house is up to temperature.

I can't imagine this would happen very much except in special circumstances,
e.g. you had the CH on and the weather became warm enough that the house
was so warm that the TRV's shut off. Then the boiler would still try and
keep the CH
loop hot, wasting energy.

You'll have to search around for a reference, or go back through the Google
Archive
of uk.d-i-y, which is searchable by keyword, if you didn't already know.

A word of warning, the room you choose to have the thermostat to go in must
not
have an alternative form of heating in it e.g. open fire, else the
thermostat will shut
off the CH. Also, the room should really have a radiator in it that is
slightly less
powerful than those in the other TRV'd rooms, as you want all the trv'd
rooms to get
up to temperature before the thermostatted room is, otherwise, by shutting
the boiler
down it will prevent the trv's from achieving their set temperatures.

I cannot see that your design meets the regs, as the boiler cannot be
completely
turned off when the house is up to temperature. Don't take my word for it
though, DYOR.

Andy.