Replacing Danfoss/Randall 3020P timer switch with Tado°

[mwatkins]

Hello all you knowledgeable folk!

First off please excuse my lack of knowledge when it comes to heating systems and electrics - I'm a computer geek not a DIYer

I've just received my Tado° system and need to fit it. It's replacing a Danfoss/Randall 3020P timer switch (no room thermostat). Boiler is a Baxi Bermuda Inset 2.

My current Randall 3020P wiring looks like this:-

The wiring diagram from the installation instructions looks like this:-

So, going from right to left: The first 3 are the mains supply:- Earth is Earth, 7 is Neutral and 6 is live.
4 is hot water on.
2 is heating on.
1 is neutral (but for what???)

The backplate for the new Tado° looks like this:-

Live and Neutral (terminals 6 and 7 on the Randall) are pretty self explanatory.

The tado backplate has no Earth terminal. I'm guessing this doesn't matter - I can just tape over the earth cable and leave it unconnected in the Tado box? Please confirm.

The yellow cable in terminal 2 of the existing Randall switch will go to the (H) terminal on the Tado.
The red cable in terminal 4 will go the the (W) terminal on the Tado.

What about the blue cable connected to terminal 1 on my existing Randall switch? According to the wiring diagram this is an 'extension' of terminal 7 (Neutral) so should I stuff the blue cable currently connected to terminal 1 of the Randall into the 'N' terminal of the Tado along with the Neutral cable coming from the mains supply?

Any help in this matter is MUCH appreciated!

Thanks very much,
Matt.

 

[Whitespirit66]

Yes, connect the blue neutral wire that's currently connected to terminal 1 on Randall into the N connection on Tado along with the neutral wire from Randall.

If you look on the Randall schematic, the 1 and N terminals are internally linked anyway, so will work with both wires to N. Not sure where the 1 wire is connected to, you may be able to trace the blue wire - maybe to boiler, pump, valve, etc. Not really important anyhow.

Does the Tado come with a room thermostat?


'Made In Bedford, England' - to think we were once so proud of the quality products we used to manufacture. Makes us old fogeys yearn for the days where everything proudly boasted 'MADE IN GREAT BRITAIN'.

 

[mwatkins]

Thanks for the reply, Whitespirit66.

I went ahead and did as you say during my lunch break and it's all working nicely. The Tado does indeed come with a wireless room thermostat. There are various 'flavours' depending on what the existing/old system comprises of.

I went for this system as my plumber said it would probably cost £250-£300 to source and fit a traditional modern digital timer and room thermostat. The Tado was £250 inc free installation (although being impatient I fitted it myself). Seems to do the trick and being a techie I like the fact that it's Internet connected and controlled by smart phone

I know what you mean about the whole "made in England" thing. Sad times.

Thanks again!
Matt.

 

[Whitespirit66]

Glad you got it all sorted and thanks for the progress update.