Question Help with installing Nest

[gierach]

Hi all

I have just upgraded my Danfoss TP 9 to Nest 3rd gen.

I must admit I thought it will be a straight swap but I am stuck with wiring and wondering whether anybody could assist?

My current setup consists of unvented hot water tank (Megaflo) and a separate boiler.

Currently wiring looks as follows:

- heating (CH ON) black
- hot water (HW ON) grey
- heating sensor two brown wires

I have below attached a photo of Nest's connectors.

Any help with connecting it would be much appreciated.









EDIT: I have got it. Sensor wires disconnected alltogether and live connected to both common for heating and hot water. Seems simple now

 

[TRIXXY DIXXY]

Hi, I'm trying to do a similar install. I only have Heating on and hot water on wires on my old Danfoss programmer. So am I right in thinking these wires go to the common terminals on the heat link? i.e 2 and 5?

 

[gierach]

Hi
The way I have done it is that heating on goes to call for heat (no 3) and hot water on to call for heat (no 6). Both commons (5 & 2) have been connected together with L (live)

 

[TRIXXY DIXXY]

many thanks for the quick response. So to double check, you have wires looping 2, 5 and L together?

Here's what my setup looked like/looks like :

 

[gierach]

Yup, that's right. It looks very similar to my old Danfoss thermostat and that's how I connected mine.

 

[TRIXXY DIXXY]

Yup, that's right. It looks cery similar to my old Danfoss thermostat and thst's how I connected mine.

Great stuff, got it up and running!

Many thanks for taking the time to help me out, couldn't of done it without you

Cheers,

Trixxy.

 

[alexbleubolt]

This is brilliant. Same problem I had. Anyone know how I bypass the thermostat wiring downstairs. I got 3 writes November London and a black one (no.3) danfloss 230

 

[AliZ4C]

Hi ppl wonder if any of you could help out with a problem I have with my nest install?! Had house fully rewired and a brand new baxi combi boiler installed (not open therm from what I can gather). Sparky installed the nest (wired to heat link) and it's all working heating wise but hot water is only working when the heating is on. It seems that when the nest reaches the set temp it completely switches off the boiler so it has no power at all to heat the hot water! Any ideas before I get the sparky back?!

 

[neilball]

Get the sparky back to rewired the boiler properly - he's either wired the heat link into the power feed to the boiler or not used the correct terminals inside the boiler (maybe wired to the "shut down" terminals rather than the heat demand terminals. Either way until it's wired properly your hot water will be compromised!

 

[AliZ4C]

Get the sparky back to rewired the boiler properly - he's either wired the heat link into the power feed to the boiler or not used the correct terminals inside the boiler (maybe wired to the "shut down" terminals rather than the heat demand terminals. Either way until it's wired properly your hot water will be compromised!

Thanks for that will give the sparky a call and get him back.... Just thought I'd something easy I could have given it a go!

 

[neilball]

You'd need to trace exactly how he has wired the controls to the boiler then compare it to the wiring diagram in the boiler installation manual so it cannot be remotely diagnosed easily here. And if you start making changes then your sparky may not be happy to come back as you've now modified his work so how does he know the problem was there before etc. As long as he comes back quickly you should leave him to it as its his responsibility to make it work.

 

[Snedds4]

@ gierach - i have the same setup as you (3 lives, 3 neutrals..) - what did you do with all of the lives and neutrals? surely they can't all fit in the L connector? or does 1 live cable go in each of the commons?