Replacing Room Thermostat - Is This Honeywell One Suitable?

[Gigagator]

Evening all,

I'll start with a little back story which is an optional read:
We moved into this new build Persimmon house in 2016 and have never been happy with the heating setup on the ground floor.
It has a Vaillant combi boiler and a Danfoss TP5000 Si room thermostat. The thermostat for the ground floor is in a very small entrance hall which contains a massive double radiator and also has the kitchen adjoined through a large open doorway. It's quite a warm area in winter especially when cooking, so we find it knocks the heat off before the living room is anywhere near the set temperature and the living room ends up quite chilly.

The current room stat is a 240v model with three core and earth going to it. Looking at the wiring and the wiring diagram I think it looks straight forward.
Am I correct in saying it is the black wire that effectively goes back to the boiler and controls whether it is to provide heat or not?


Even though the house is all plasterboard, I don't want to chase walls out or make holes to pull a cable through to the living room.

I believe a wireless room thermostat with a receiver and wireless controller would be the ideal solution here and I could just hook the receiver up to the current location of the wired thermostat, and then mount the wireless part in a sensible location in our living room. Does that sound feasible?

If I'm along the right lines with all the above, I am looking at the following Honewell T4R wireless thermostat - https://www.tlc-direct.co.uk/Products/HWT4R.html

Looking at the installation instructions for the T4R am I correct in saying that it would be wired up as follows using the current cable:
- Grey to neutral
- Brown to live
- Sleeved CPC to earth
- Keep the brown link wire from live to terminal 'A'
- Black wire to terminal 'B'

Many thanks in advance for the advice. I am comfortable and competent replacing light switches, sockets and light fittings but this is the first time I've worked on a room thermostat.

 

[CBW]

Pretty much yes, but there’s an additional L terminal where you could link to A which would work.

 

[ericmark]

Your problem is common, I have the same problem, and the cure is multi-thermostats. In the main we already have them, the TRV and lock shield valve can limit a rooms temperature to a level below where the wall thermostat turns off, in fact there is very little use for the wall thermostat.

With the wall thermostat set a max so it never turns off, the TRV and lock shield valve can control each room spot on. However it has one major problem, as we get warm weather the boiler will reduce output, and then start to cycle, but it can't switch fully off, so either the TRV has to be linked to some hub or wall thermostat, so we need one which when warm weather returns will turn off boiler.

The TRV's can have electronic heads with a programmable feature, and this feature can also report to phone or PC the current and target temperature depending on make, and this helps set the lock shield valves, most gas boilers are condensing and to be condensing they need to modulate, so the whole of the heating is under analogue control turning up/down not on/off, any on/off control can mess this all up. It will work on/off, but analogue is better.

I have 4 types of TRV in my house, 5 mechanical (toilet and granny flat) 5 eQ-3 bluetooth will only link to one phone, 3 Energenie second control picture don't really like them as can't be manually set, and one TP-Link (Kasa) to replace an Energenie one smashed by carpet fitters. Since I have Nest Gen 3 which is a bit useless and will not connect to TRV heads I am a bit stuck, but there are many wall thermostats designed to work with TRV heads, EvoHome was about the first, but now there are loads, Wiser, Tado, Hive etc, And it seems the Moes may also do a cheap version.

You will likely have one wall thermostat so cost of that is not so important, but in my case I have 14 TRV heads, so you need to decide how much to spend on the heads, and get a wall thermostat to suit. Clearly you can do it in stages, but read about them first and decide the final goal.

I made a mistake, I tell you so you don't make same mistake, I was told Energenie worked with Nest so started with TRV heads then got the Nest, and it does use same app, but does not really work with it, for one it works wrong way around, the TRV should tell the wall thermostat when to turn on boiler, and mine if they worked would do the reverse.

I looked at Tado and everything seemed to be secret so can't work out what you want, and Hive the wall thermostat needs to be in a room which never exceeds 22ºC or it stops taking a demand for heat, the wiser seems about the best as the TRV's work out how long it takes to heat the room, but likely you don't need smart TRV heads in all rooms, just some key ones.

 

[Gigagator]

Thanks for the responses. I am going to go ahead and order that Honeywell stat from TLC.

Eric, silly as it may sound coming from someone who is 31 years old and an IT professional, but that all sounds too complicated for me!
I think it comes from spending all day fixing IT issues for other people - the last thing I want to come home to is more technology! Hence why I also drive a 20 year old Rover 25; as analogue as I can get without a carburettor.

Thanks for the information though, was very interesting.