Thermostat replacement question

[Verdi]

Hello all,
I'm after advice on replacing my existing thermostat, a Danfoss RET 230P, with a Tado thermostat, and have a wiring question. I normally use an electrician as the most I have done in the past is replace sockets and switches and moved ceiling lights. I'm wary of electricity as I once got zapped wallpapering

I'm hoping the photo attached helps - excuse the dodgy photoshop skills. The wires in my existing thermostat are labelled N,L, ON,OFF, and COM. ON,OFF,and COM are labelled 1,2,&3 above so I intended to match these as per the diagram supplied with the Tado instructions.

I'm assuming that L and N will go in the ports marked A and +, with N connecting to the A port and L to the + port. Is this correct?
In my existing thermostat I have a wire that runs from the L port to the COM port. Do I replicate this in the Tado?

Many thanks for any help you can provide.

Untitled

• Verdi
• 3 Apr 2015
• 1

 

[EFLImpudence]

https://www.tado.com/gb/thermostat-setup

 

[Verdi]

Thanks For the reply. I started there and went through the installation workflow but all the info differs from the wiring in my current thermostat.

 

[EFLImpudence]

I am not familiar with the product but it seems you need to connect the brown and black to 1 and 3.

Terminate the grey in a piece of connector block and position safely out of the way.
The link is not needed.

 

[Verdi]

Well I was way out then! Thanks for the reply - much appreciated. I'll update one it's done so others can see.

 

[ericmark]

It took some time to find the instructions and it seems you have two systems and you can use either.

The NO - NC - COM is the standard old system I have always wondered which to use each time I pick up a thermostat as we really have no idea of how a relay is operated, but in general flat battery means no heat so NO and COM will be the correct connections for heating. That's how I remember it.

The unit has also three blanks to park unused cables often you also have a neutral and earth which are not used. Your picture does not show the spare holes so may be not on yours.

The A - + is for digital interface with the boiler and it is unlikely you will use these terminals there is a maximum of 30 volt on these and if connected to mains likely it will blow the unit.

So it would seem you only use two wires. Any others just need taping up so they can't touch anything.

It would seem old wiring is

so wired that went to N, L, are not used. I would expect there were no wires to 3, OFF on original unit.

All power is from the two AAA batteries my unit at home also uses two AAA batteries which should last two years and give a warning icon when going flat but bitter cold experience it stops working before the sign lights and so I swap batteries every year needed or not.

 

[Verdi]

That's great stuff, thanks for the time and effort in your response.

Looking at the instructions now with what I've been told here, and looking at the Danfoss instructions it makes sense now so I'll have a bash.

Again, thanks to you both.