Siemens RWB29 + Remote stat?

[Billv84]

Hi,

Happy new year all!

I hope someone can help please;

I have a Remeha boiler which heats radiators and a hot water tank. It is currently controlled by a Siemens RWB29 programmer, which can be used to set the water heating times and central heating routine. We have always nust pressed the '+1' button for the central heating when its cold, which just runs it for an hour, on demand.

However, we have a 6 month old in a small bedroom and as the temperature outside has dropped, she is waking up cold in the night.

Ideally, we want a portable thermostat to leave in her room to keep it at a steady 17/18°.

There is an old Honeywell stat fixed in a downstairs hallway (guessing its 1980s). Taking the cover off it reveals that it is connected with 3 wires. When i leave the heating control on the programmer to 'on', the stat does seem to flick the boiler on and off, but seems to be massively innaccurate!

Could anyone recommend a simple solution to what i want?

I'm not hugely bothered about a 'smart' control, but would buy one if it made sense. In a previous house we had a little portable dial which was ideal (think that might have been Siemens also).

Im not a plumber or sparky and dont really want to spend loads. I was hoping i could just buy a unit to replace the fixed stat which would then connect wirelessly to a portable control.

Any ideas hugely appreciated! Many thanks!

 

[CBW]

Depending on the 3 wires inside the thermostat, might not have a neutral wire (wider temp swings without). Are you looking just to upgrade the thermostat? If so, plenty of wireless thermostats to choose from. Post photo of wiring at Honeywell to begin with.

 

[ianmcd]

You do realise if you do as you propose that when the heating comes on in the babies room, all the other rads in the house will come on at the same time ? probably cheapest and easiest to buy a small oil filled electric radiator if just for the one room, if you want all the rads on buy an RF thermostat, mount the receiver next to the RWB29 and wire it into there, and link out the existing thermostat, the new thermostat will be battery powered, so can be taken up to the babies room

 

[Billv84]

Depending on the 3 wires inside the thermostat, might not have a neutral wire (wider temp swings without). Are you looking just to upgrade the thermostat? If so, plenty of wireless thermostats to choose from. Post photo of wiring at Honeywell to begin with.

Thanks for the reply Chris. Yes, i guess i just want an upgrade to the stat so that i can move it between rooms and have it more accurate.

Below is the wiring - i have wires into connectors 1, 3 and 2

 

[ianmcd]

read my earlier reply, you cant put the receiver there, easiest place would be next to your programmr then take the thermostst to any room you want

 

[Billv84]

You do realise if you do as you propose that when the heating comes on in the babies room, all the other rads in the house will come on at the same time ? probably cheapest and easiest to buy a small oil filled electric radiator if just for the one room, if you want all the rads on buy an RF thermostat, mount the receiver next to the RWB29 and wire it into there, and link out the existing thermostat, the new thermostat will be battery powered, so can be taken up to the babies room

Hi Ian, fair point about an oil filled jobbie, but its such a small room that it takes maybe 15 mins with heating on to get up a few degrees. Plus, the hallway where the fixed, old stat is, is always cold, so as good as useless. A portable one seems more sensible, just hoping i can find one that i can easily wire in...

 

[ianmcd]

Hi Ian, fair point about an oil filled jobbie, but its such a small room that it takes maybe 15 mins with heating on to get up a few degrees. Plus, the hallway where the fixed, old stat is, is always cold, so as good as useless. A portable one seems more sensible, just hoping i can find one that i can easily wire in...

They all wire in exactly the same, sadly most of the wireless RF stats on the market just now are programmable so probably not what you want, but you can set then to constantly on and just use the up and down temp buttons if you want

 

[CBW]

Ok so the neutral wire is there if it’s as you say, you can place receiver there and place room thermostat wherever you want. The other option is leave existing thermostat wiring, and connect live and switched, safely terminate neutral and use a digital battery operated thermostat.

Post edited to save confusion.

 

[ianmcd]

sorry I misread your post when you just mentioned the two lives, if you also have a neutral that makes it a lot easier, you can just fit the receiver, where the existing thermostat is, although you will have to swap the live at the other end of the cable to a permanent live , the switched live remains the same as does the neutral

 

[Billv84]

Thanks very much for the input, much appreciated.

So by the sounds of it, should i be able to buy something like this;
(Siemens RDH100RF)

And just fit the receiver part where the old stat is?

If thats the case, is there much advantage to splashing more for a smart one with a phone app (or would one of those actually be any easier the fit?)

 

[CBW]

Yes that’s fine, but you’d need to place a link wire between L and Lx.

 

[ianmcd]

If thats the case, is there much advantage to splashing more for a smart one with a phone app (or would one of those actually be any easier the fit?)

They are all exactly the same to fit, just depends on what you want it to do, the advantage of one that connects to your smart phone is you can see what temp the babies room is, or wherever the stat is placed, on your phone

 

[stem]

You don't mention if you have thermostatic radiator valves on any of your radiators, but if you do, there should not be a TRV fitted to the radiator in the room in which the room thermostat is located, as it can interfere with the correct operation of the room thermostat.

As this appears to be a temporary arrangement until your daughter gets a bit older, removing the TRV head, or setting it to maximum would suffice. If there isn't a TRV nothing to worry about.