Nest launches in uk tomorrow...

jouster

Cheeky get

Monty Nine

Greg, turn down the radiator thermovalves in the hottest rooms to stop them getting so hot?

Greg Hook

That sounds obvious doesn't it, but even doing that the boiler is still running as the main thermostat in the boiler is in the coldest room and the main radiator in the hall doesn't have a thermovalve on it. So to sum up a bit of an inefficient system we have! This is why I think a solution like Nest or something similar would be a great idea.

Rorifett

Is it not possible to fit the valves fairly easily to radiators?
And when you said it's on a 24 hour timer did you mean one of those on/off dial things you see on old wall hung heaters? If you could set more than 3 programmes throughout the day you could just blast hearing in an hour on hour off hour on kinda way at night?

Greg Hook

Probably but we have a lot of radiators, I just want a simple system that I can set the temp of the main living area and it keeps it to that. I don't want to go messing about with thermostats on radiators several times a year.

Steroc

If the newer boiler is in the same place as the old one was then there's no reason the installer couldn't have connected the old thermostat to it and wouldn't have cost him anything apart from a few minutes of his time. May still be possible to do if the wire is still there.

Rorifett

Was just thinking of that hallway one, think TRVs are pretty cheap outside of sorting the full system

IronGiant

Greg you sound like you have a very basic system just like we had in our first house.  The argument was the fewer parts it had the less there was to go wrong .

The thermostat at the boiler didn't respond to room temperature only the temperature of the water returning to it.  The idea being that when all the rooms are warm and their TRVs shut down the water coming back will be hot enough that the boiler can turn off.  Same for the hot water, it relies on the water in the tank reaching the same temperature as the hot water in the pipes, so nice hot water returns to the boiler and the boiler can shut down.  There was no independent switching to water or heating when the boiler was on water went to both, only when the water returning to the boiler was hot did it shut down.  Then there was a big manual switch in the airing cupboard with a summer winter setting so you could isolate the radiators in summer.   The major downside, apart from the lack of finesse were that the temperature of the circulating water determined the temperature of your hot water so you had to set it at a safe level, which isn't an optimum one for heating radiators and primarily that the boiler was always keeping it's own water at the set temperature, so was continually cycling water through pipes even when everything was at temperature. In other words, assuming the boiler was set at 60 deg, as soon as the water in the boiler itself cooled below that, off it would go again, circulating water around the system until it was nice and cosy again.

It would also be impossible to control such a system with the nest because you could never be sure you had any hot water, it would only ever turn the boiler on when the radiators required it.

Can you check whether your existing timer has separate hot water and heating switching Greg?  If so you may be OK.  And you can ignore the boiler thermostat

IronGiant

Jouster, how does it "learn" your movements so that it knows when to come on and when to go off?

Greg Hook

This is the front of our boiler:

You can see just a few controls. From far left we have the pressure gauge, hot water temperature selector, mode selector switch (water, heating), heating temperature selector and finally the crappy manual timer.

We don't have a hot water tank, it's a combi boiler.