Replacing my heating Thermostat (room stat )

[Paul6952]

I have a Danfoss RMT230 room stat and having had my boiler replaced the engineer removed the programmable timer and all I am left with is the basic timer on the combi ( a Baxi platinum combi 33 ) and the Danfoss.
Would it be possible to replace the Danfoss with a programmable thermostat to control the boiler using the existing wiring?
See exiting wiring below

Danfoss RMT 230

• Paul6952
• 10 Dec 2017

If so what would anyone recommend?

My current boiler controls are below what would I do with them or how do I control the boiler with the new stat?

Baxi Combi 33

• Paul6952
• 10 Dec 2017

Any advice would be appreciated

Cheers
Paul

 

[muggles]

Yes you could replace that with a programmable stat quite easily. Have a look at the Honeywell T6 Lyric - a very well priced smart thermostat which will fire you into the 21st century with app control. Should slowly pay for itself if you set it up right.

 

[D_Hailsham]

If you set the existing timer to constant (I) the programmable stat will then control time as well as temperature.

The RMT terminals are:
1. Live
2. Not used
3. Switched Live
4. Neutral

How you wire up a prog-stat will depend on which one you have - they will all do the job. Do you have anything in mind, e.g Honeywell?

 

[Paul6952]

Thanks Andrew looking at the link you sent the Honeywell controller looks ideal.

 

[Paul6952]

Hi D_Halisham my RMT seems to have no wire at terminal 3

Blue wire to no 4
Red to no 1
Yellow ( with red sleeve) to no 2
Earth seems to go to back of unit

 

[Paul6952]

Yes you could replace that with a programmable stat quite easily. Have a look at the Honeywell T6 Lyric - a very well priced smart thermostat which will fire you into the 21st century with app control. Should slowly pay for itself if you set it up right.

 

[Paul6952]

Hi looking at the Honeywell Lyric T6 a unit needs to be wired into the boiler is that correct?

 

[muggles]

Correct yes, you use two of the wires to your existing thermostat to connect into a receiver box, then connect the receiver box into the boiler using Live / Neutral / Switch Live.

 

[D_Hailsham]

Hi D_Halisham my RMT seems to have no wire at terminal 3

Blue wire to no 4
Red to no 1
Yellow ( with red sleeve) to no 2
Earth seems to go to back of unit

My bad. I should have written:

1. Live
2. Switched Live
3. Not used
4. Neutral

For some unknown reason the terminals are numbered out of sequence, i.e 4,-, -,1,3,2.

There are two version of the Lyric - wired (T6) and wireless (T6R). The PlumbArena page shows the wired, but the pdf shows the wireless.

The Honeywell Lyric Support page has more information.

 

[ajsdoc]

Could this thermostat work as a standalone thermostat without faffing with the relay box? I'd like a smart thermostat, currently have a wired Honeywell simple dial thermostat and then a Honeywell programmer next to the boiler.

Would the smart function work if just using the thermostat with the programmer for heating set to continuous?

Guess I can countenance and understand fitting the thermostat - what does the relay box actually do?

 

[muggles]

Could this thermostat work as a standalone thermostat without faffing with the relay box? I'd like a smart thermostat, currently have a wired Honeywell simple dial thermostat and then a Honeywell programmer next to the boiler.

Would the smart function work if just using the thermostat with the programmer for heating set to continuous?

Guess I can countenance and understand fitting the thermostat - what does the relay box actually do?

The relay box converts 230v AC to a variable DC power source of approx 20v for the thermostat. Connecting the thermostat without the relay box will result in an expensive bang

 

[ajsdoc]

Ah...

The existing programmer is an ST9400c which is an "industry standard backplate". Don't suppose the relay box is compatible with this without faffing with re wiring.

(Already almost decided not to bother and stick with the simple wheel thermostat, but I do like the idea of a smart thermostat..)

I appreciate your replies.

 

[ajsdoc]

Think I've found my answer - can't control the hot water.
Think Tado may be the solution for me.