New wall thermostat needed

[doorstop12]

Hi all

I wonder if you could help me please. I'd like to replace my old Sunvic TLX 2259 with a newer thermostat. I'm hoping for a straightforward swap (anything too complicated with electrics is beyond me) but would prefer a digital device. Could anyone recommend one?

I have a British Gas UP2 control panel in the airing cupboard which is sufficient for programming times, so I'm open to the idea of a non-programmable stat, but not against a programmable one either.

My boiler is ancient (Apollo Fanfare 15/30si) so I'm looking to keep things fairly simple and not go wireless.

The current stat is wired as per the attached photo so, according to the wiring diagram;

Red = switched live
Yellow = permanent live
Blue = neutral

Any advice and recommendations gratefully received.

Thank you

 

[stem]

Any standard room stat will replace that. If you get an electronic, battery operated one that has a digital display then you will need only use two of the wires [Red & Yellow]. This type are generally more accurate than the mechanical movement type that you have now.

I would suggest that you have a search for one that you like the look of, and that fits your requirements, then post back the make / model details on here and someone will be able to confirm its suitability and tell you how to install it.

Personally in your case, I would fit a Honeywell, Drayton, Siemens or Danfoss, and avoid the cheaper obscure models that some online retailers promote. As with most things in life you get what you pay for.

 

[doorstop12]

Thank you very much for replying.

What about the Honeywell DT90E?

https://www.screwfix.com/p/honeywell-home-dt90e-digital-room-thermostat-eco/41365

 

[Harry Bloomfield]

Thank you very much for replying.

What about the Honeywell DT90E?

https://www.screwfix.com/p/honeywell-home-dt90e-digital-room-thermostat-eco/41365

That will be fine and almost a straight swap for yours.

 

[doorstop12]

Great, thank you.

I've just checked the Honeywell help site for the wiring diagram. It looks like:

Yellow to A
Red to B
and tape off/ choc block blue to make safe

Please let me know if you disagree.

 

[stem]

Sounds good to me

Edit.
Convention has it that the 'Permanent Live' [Red] is A, and the 'Switched Live' [Yellow] is B. But as a thermostat is just a simple on/off switch, in reality it will work fine either way around.

 

[doorstop12]

Thanks again

Any advice on making the neutral wire safe? I was intending to tape it but Google tells me that would be unsafe. Do I need to use a terminal block? If so, any recommendations on what to go for? (Screwfix, ideally)

 

[stem]

Indeed, insulation tape is prone to loose its adhesion and fall off, I use one of these. You can get them from any hardware shop or DIY shed....

.....and Screwfix

 

[doorstop12]

Great, thank you. 16A would be suitable, I assume?

Looks straightforward enough (famous last words!...)

 

[Harry Bloomfield]

If you have a single 16amp and it will fit in the space, then use it. A single 5amp one would be adequate.

 

[stem]

If you click on the word 'Screwfix' in my post above it will show you a 6A terminal strip.

As you are only using the terminal as a method of insulation / isolation, there won't actually be any current flowing through it at all so this is one instance 'where size doesn't matter' and a smaller terminal will probably contain a thin wire more securely.

Even if there was current flowing through the terminal, the boiler should be fitted with a 3A fuse anyway, so 5A or 6A is more than enough.