Room thermostat not connecting to CH boiler

[ericmark]

Would the individual stats on the rads influence anything??

In most cases' no, but in my house yes, one TRV head is linked and can cause the boiler to fire. This house had all sorts of problems with central heating when I moved in. My plumbing skills are very poor, so I got a plumber to do the pipework, could not believe it when he admitted he did not know how to do the wiring, not a problem for me, as I did.

If all my rooms were heated 24/7 it would cost a fortune. But if I set the thermostatic radiator valves (TRV) then with no wall thermostat the waste in mid-winter would not be that high. Spring and Autumn yes a problem, but mid-winter, the boiler rarely switches off with a modulating boiler, as the name suggests, it just turns down (modulates) and mid-winter this means it gains the latent heat from the flue gases unless the boiler is oversized.

In spring and autumn however, there are days when heating is not required, so we are told to fit a wall thermostat in a downstairs room, as heat raises, which is normally kept cool, as don't want it to fire up on a day it is likely to get warm, with no outside doors, as clearly opening a door will cool the room and start the heating when not required, and with no alternative heating, as that would stop boiler firing when required.

Well, don't know your house, but my house no such room. I still think sticking micro switch in a motorised valve is most likely problem, but I found with this house, the wall thermostat, which had to go in the hall, as that was where the wires went, was not good enough, the simple reason was the hall cooled too slowly, I can adjust heating speed with lock shield valve, but not the cooling speed.

So the answer is a hub, with the option of many devices all able to fire the boiler, main house I have 3, the original thermostat, left connected as it can also control domestic hot water (DHW) a linked TRV in my wife's bedroom, likely coldest room in house, and a wall thermostat in the living room, as radiators next to outside walls, so can start the boiler prematurely as colder than the room in general until the heating starts. Still have TRV to stop over-heating, but wall thermostat triggers the boiler. Wife likes bedroom on cool side, so TRV set to 14°C daytime, 17°C before she goes to bed.

My boiler does not modulate, so not as much of a problem turning it on/off, but each home is different, and there is no magic system which suits all. Likely, a Drayton Wiser control with all linked TRV heads will not be far out for most homes, as long as radiators on internal walls, but one has to consider installation cost against running cost, £600 for the control, or £600 extra for oil/gas over say 15 years, which will you go for?

Home size does make a difference, two up, two down, likely motorised hard-wired valves will work well, but with 14 rooms, looking at linked electronic TRV heads, I have 8 rooms rarely used, some on bottom floor, some on middle floor, and some on top floor, so want to turn those rooms down.