Tado system to replace Hive - Wiring Help

29 Dec 2020
Reaction score
United Kingdom

We have a Baxi Assure 30 combi and have used a hive system with standard TRVs bar 1 rad for ages. We don't have a hot water tank or anything like that, no multi zones. We basically boosted the heating as and when we wanted and hot water is on demand. We've bought a Tado Wireless Smart Thermostat starter kit V3+ to replace the Hive. We have 8 rads and have 7 tado smart radiator thermostats to go on once this is sorted.

The boiler was fitted 2 years ago and the existing Hive was connected to it by the installer.

I've followed the Tado instructions up until the wiring part, there's an extra wire on the (1) connection on the Hive wiring which him not sure what to do with.

Am I correct in saying based on the Hive wiring (image) that:

Hive Bridge wire on L & 1 to Tado Bridge wire to (L) and (CH COM)

Hive Blue on N to Tado Blue to (N)

Hive Brown on L to Tado Brown to (L)

Hive Black on 3 to Tado Black to (CH NO)

Im not sure what to do with the Grey wire that is in 1 of the Hive, do I just put that on (CH COM)?

Also noticed the earth on the Hive wiring, when I trace it back in the boiler its just a loose wire, hasn't ever been connected to anywhere as its not even stripped, is that not connected on purpose or just poor workmanship from the installer? Looking at the Hive wiring connections i'm guessing the latter.

Thanks in advance :)


  • hivewiring - 1.jpeg
    hivewiring - 1.jpeg
    248.3 KB · Views: 46
Sponsored Links
Be very careful you don’t mix up 240v and lower voltage control side on the boiler.

By the way, Tado wiring issues have been raised on here a few times very recently so if you do a search you might find the answer - there’s a very helpful member who has helped a few times on this issue and his answers are in the threads.
The picture of the existing Hive that you posted, is wired for 240V (the clue is the link between terminals L and 1. If it was low voltage the link wouldn't be there)

It looks like the grey wire is presently connected to L via the link between L and 1. In which case it should remain connected to L.

There are quite a few variations of TADO thermostat, and they are wired differently. Which version do you have?
I've had a look at more instructions and gave this a go.
The Boiler wiring blocks (white) from top to bottom left hand side, the first 2 wires seems to have been connected the wrong way around, I haven't swapped them over boiler side but I have Tado side. Grey should be at the top and the black 2nd. Those are the wires that go to the Hive/Tado. The next one is the earth which i've stripped and reconnected, that also goes to the Hive/Tado. The Blue and The Brown wires are the N and L that go to the Hive/Tado.
The tado wireless receiver connections i've done the following:
Blue to N
Brown to L
Grey (which should be Black) CH COM
Black (which should be Grey) CH NO
Green/Yel to Earth
I've took the bridge out.

Everything seems to be working fine now, but I still don't trust that I haven't made a mistake and hopefully someone will be able to say so.

Thank again :)


  • hivewiring2 - 1.jpeg
    hivewiring2 - 1.jpeg
    323.8 KB · Views: 37
Sponsored Links
Here's the boiler wiring diagram.


From your photo, the black wire shown in boiler terminal 1 below (counting from the top) is the 'switched live' indicated by the > arrow and should come from the switched live of the thermostat [for Hive that's 3] I can't be specific about the Tado terminals because you still haven't said which version of Tado you have.

The grey wire shown in your boiler terminal 2 below is the 'permanent live' indicated by the 230V and the < arrow in the diagram above. That should go to the live at the thermostat. Although in your first photo of the Hive there is also a brown wire in L, so it could be getting a live from there also. Not an issue if they both come from the same 3A Fused Connection Unit.

this one.jpg

I hope you've tidied up the Hive connections when you moved the wiring to Tado, those in your first photo are terrible and run the risk of a short circuit, there should be little or no copper on show outside of the terminals and no whiskers poking out whatsoever.
Last edited:

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local