Help wiring Tado V3+ receiver from EMT2

Mdp

Hey folks!

I’m trying to wire up the V3+ receiver in place of my current ancient Scottish Gas EMT2 receiver and separate thermostat.

My issue is that I’m not sure which wires should correspond to the ones on the Tado receiver. Additionally, when I tried to decommission the thermostat I found that my boiler would not fire up for heating or hot water.

Here is the setup I’m working with; https://imgur.com/a/NGDcie9

1. This is the wiring of the existing receiver (if the image is unclear, there’s a blue and a grey wire in N, a brown in L, a brown in 1, a brown in 3, earth, and a blue and black wire have been capped)
2. This is the wiring of the thermostat
3. The new Tado receiver

For additional context I have a Potterton combo boiler, and the receiver and thermostat are next to each other in my hallway.

Any help appreciated, let me know if I haven’t provided enough context to give a helpful answer.

Cheers!

Mdp

Bumping this up in case anyone can help!

Jturner

Well looking at the pictures do you two switches on your timer or one by how it's wired just looks like one a picture of the actual timer would help

Mdp

Thanks JTurner, here an image of the thermostat and receiver

https://imgur.com/a/5y6mEtW

Montage

You should be able to unwire the current Stat (at the timer), but removing the brown, grey and black.

The second black in the choc block must be the switched live back to the boiler to fire it for CH.

The brown in 1 is essentially the feed for the SL by the looks of it.

Jturner

as Montage said the brown wire in 1 would goto CH COM and the one in 3 would goto CH NO

Mdp

Ok thanks, I’ll try that!

Mdp

Hi @Jturner @Montage, I tried what you suggested last night but for some reason or other I can't get the receiver to talk the boiler. Once it's all wired up the CH light on my boiler no longer lights up.

I could be way out, but I feel like the 'stat has something to do with it. As soon as I disconnect the wires to this, the CH light doesn't come on any more. Could that be possible? Any suggestions?

Thanks!

Montage

You are aiming to disconnect all the wiring that runs to the stat and do your work where the timer is.

At the timer you should then have

1 blue

2 brown

1 black

1or 2 earths

Does that match what you have?

Mdp

So at the timer I have:

N: 1 blue, 1 grey

L: 1 brown

1: 1 brown

3: 1 brown

2 Earth wires

1 black wire (in a white splice block, which isn't connected to anything else)

Thanks

Montage

That does sound like too many wires, but I'll continue. I hoped you'd have fewer after removing the stat wiring to the timer.

The black wire in the chock block. This had 2 black wires and one of them went to the old stat, I presume.

On the basis that all the brown wires are equal, you can use one as the L to feed the Tado receiver (Blue to N).

Then L to Com and black to NO (these are the ones that connect to fire up the HW).

IF I'm wrong about the black wire assumption then hold fire.

Mdp

Thanks @Montage, I see what you mean.

Here's a clearer picture of what is behind the old timer: https://imgur.com/a/vKVlHZR

So to recap, there's 9 wires at the timer (I forgot to say there's a blue wire in the block if that changes anything) ;

N: 1 blue, 1 grey

L: 1 brown

1: 1 brown

3: 1 brown

2 Earth wires

1 black and 1 blue wire in a block

So to remove the wiring for the stat, I should: Remove the grey from N, remove 1 of the brown wires (which one?) and then what should I do with the blue/black splice?

Thanks in advance for your patience

Montage

Take this in good spirit, but it's like that game with the ball under the cups. Just when I think I've worked it out...

If you just wanted to get it working you'd connect the receiver where the timer now is - L, N, Com(wire 1), NO (wire 3) and then connect the brown to the blue at the stat, cap off the grey. That'll work.

The tidy method is what I was trying for. Remove the grey, the black and the brown that is the other end of the cable from the stat (prob wire 3). Then the wiring for the receiver would be L, N, Com (brown) and NO(blue).

Yes, the blue wire changed everything. I think that's the SL (switched live) heading off to the boiler.

Hope that all makes sense.

Mdp

@Montage I think your comment is completely fair and perhaps even too kind 😂

Thanks so much for your patience and understanding, I will give this a try tonight!

All the best