Thermostat Wiring

[Stapes]

Hi everyone, wonder if someone can guide me on this please? I bought a Tado to replace a Honeywell T6360B but stupidly, i forgot to take a photo of the wiring before taking it off the wall. I then (second act of stupidity) followed a YouTube video which told me where i thought the wires should be connected, but whilst the Tado unit works, it doesn't fire up the boiler when adjusting the temperature (and it's getting bloody cold in my house).

I know that connectors 2, 3 and 1 (per the first pic) were used on the Honeywell as these are the screws that have been loosened. I have blue, brown and green/yellow wires coming form the wall (as in the second pic), question is, where should these connect to the Tado? Pics for reference:

https://ibb.co/DGKbFpG

https://ibb.co/rcJ480f

Many thanks in advance guys.

 

[bill01803]

As the the Honeywell nedded a neutral it could be the blue is the neutral and the switched live is the green/yellow besdt to check at the other end first though.

 

[Stapes]

As the the Honeywell nedded a neutral it could be the blue is the neutral and the switched live is the green/yellow besdt to check at the other end first though.

Thanks for your reply. Now this could be my third act of stupidity in a day, but is this something i can test by switching the wires around? Or can this cause damage to me/the unit?!

If not, how could i check at the other end? I know it doesn't sound/look like it, but i'm usually fairly adept at these kind of things. Should i hire a pro instead?

 

[telectrix]

a photo of the terminals in the boiler would help.

 

[Stapes]

a photo of the terminals in the boiler would help.

Thanks so much for your reply. Do these help?

https://ibb.co/884S1pG

https://ibb.co/hyDMrNJ

 

[littlespark]

As the the Honeywell nedded a neutral it could be the blue is the neutral and the switched live is the green/yellow besdt to check at the other end first though.

Green/yellow is switched live?

doesn’t sound promising.

 

[Stapes]

Green/yellow is switched live?

doesn’t sound promising.

Not promising how?

 

[littlespark]

Green and yellow should only be used as a cpc or earth. So whoever wired the stat in the first instance didn’t do it right.... IF indeed it is being used as a switches live

 

[telectrix]

take the green /yellow out of terminal 2 at boiler. take the blue of the same cable out of terminal 4 and put into terminal2. at stat, brown and blue as your picture. use the green/yellows as earths.

 

[Stapes]

Green and yellow should only be used as a cpc or earth. So whoever wired the stat in the first instance didn’t do it right.... IF indeed it is being used as a switches live

Do they make sense at all if the first pics at the top of the page are taken into account? Apologies for asking so many questions - should i get a pro to look at it or reckon this is something i can resolve myself?

 

[lozarus]

Green and yellow should only be used as a cpc or earth. So whoever wired the stat in the first instance didn’t do it right.... IF indeed it is being used as a switches live

Worth a note that it is flexible cable, so doesn't pose the same risks as if it were T&E (exposed conductor / CSA difference). I agree with you entirely that it's not right and don't approve if it - but there was some debate about it. It was mentioned on Voltimum as being 'frowned upon' but it was answered that as long as it's oversleeved it would comply with BS7671. It wouldn't allow for identification along the whole length of the cable, but not sure how much impact that would have in this example - so it potentially could be remedied quite easily with some brown sleeving.

As for the OP I'd say some basic testing needed to identify the cores, unless each flex is visible throughout the entire run - in which case it could be established visually

 

[Stapes]

take the green /yellow out of terminal 2 at boiler. take the blue of the same cable out of terminal 4 and put into terminal2. at stat, brown and blue as your picture. use the green/yellows as earths.

Super helpful, thank you mate. Just for clarity, which is the earth connection on the Tado?

 

[Stapes]

Worth a note that it is flexible cable, so doesn't pose the same risks as if it were T&E (exposed conductor / CSA difference). I agree with you entirely that it's not right and don't approve if it - but there was some debate about it. It was mentioned on Voltimum as being 'frowned upon' but it was answered that as long as it's oversleeved it would comply with BS7671. It wouldn't allow for identification along the whole length of the cable, but not sure how much impact that would have in this example - so it potentially could be remedied quite easily with some brown sleeving.

As for the OP I'd say some basic testing needed to identify the cores, unless each flex is visible throughout the entire run - in which case it could be established visually

Great reply thank you mate. Reassuring that even though it might not be perfect, it doesn't sound particularly unsafe.

No idea how to visually establish the flex given that the wires are hidden behind the walls. I think you know by now that i don't even tick the novice box on this one.