Nest V3 installation to Multizone system

[Pauli11]

Hi,

I have successfully fitted a V3 thermostat on a yPlan system in my holiday home.
I have two more to install now in my own house, which has 3 zones, bedrooms (heating), main house (heating) and Hot water. This I presume is an Splan install.

The install is obviously different to my last one, but the junction box looks totally different to the other houses wiring.

There are 3 valves. 2 white plastic ones for Living area heating zone 1 and bedrooms heating area zone 2, just below this junction box, and a metal incased valve on the hot water tank. The wiring is as follows (with reference to Junctions 1-10 on the choc box above from the left)

Hot water tank valve has 5 wires, orange to 10, grey to 1, black to 2, blue to 9 and earth to 8
Heating valve 1 (living)has 4 wires, orange to 10, grey to 1, blue to 2, and brown to 5.
Heating valve 2 (beds) has orange to 10, grey to 1, blue to 2 and brown to 7.

I have a black cable coming through the wall with red to 10 (on top in the pic), black to 9, and green to earth 8 (could this be the boiler which is located in the garage?)

from the grey sheaths coming down the conduit, there are 2 reds going to 4, a yellow to 5, a red and yellow to 6, and a yellow to 7 , some of these at least are likely to come from the hall and bedroom stats.

I am only concerned with the living area (zone 1) and hot water install at the minute, once that is successful, Ill connect up the 2nd Heat link. I should know where I am by then.

On the heatlink, I am running live to live, and n to neutral from the switch. I am then linking L, 2 and 5 together.
1 and 4 remain unconnected?
This leaves 3, and 6 to the heatlink.
Im thinking 3 on heatlink goes to 5 on the choc block to meet the brown wire from the living area heating zone valve?
I have not located the cylinder thermostat, just the metal valve as described above. I understand 6 on the heatlink needs to connect to the cylinder stat?


This is the living area thermostat. which of these two wires would be the wires that attach to t1 and t2 on the heatlink for nest 12v power? and what should I do with the third?

This is the bedroom zone thermostat. Easier this time as there are only two wires. Ill join them and run a continuity test.
Why would the first stat have three wires, and the second only 2 wires?

A lot of questions here I know, but Im very close. And after completing a successful yplan install a few days ago, I am determined to get this one sorted as well.

 

[Pauli11]

anyone?

 

[Dan Robinson]

A please and thank you would be nice. As well as reading the many threads already covering this tiresome subject.

 

[Pauli11]

Here we go again.


You post a serious question on a DIY forum and get this crap as a reply.

Why is it that this forum seems to now be polluted by self righteous ****s that have little interest in actually helping someone, and more interest in dissing people looking help.

Its always those with thousands of posts, no doubt a "Qualified Professional" and ultimately little better to do than annoy others.

How do I know that? Apart from suffering the same nonsense in other threads I have been involved in, I have actually read every other Nest installation thread "covering this tiresome subject", and it is littered with smartarsed posts from people like you.


Thankfully, the number of folk here willing to help and offer advice outnumber the smartarse brigade, and you will find my manners in truly thanking those people is not open to scrutiny.

In the meantime, you might want to look up the meaning of hypocrisy, because you are certainly not practising what you preach.

Don't worry Steely, I have a thick skin; I'm perfectly comfortable too with my intellect and don't feel the need to act the pompous old fart. Site banter is far more entertaining and genuine than the kind of office politics and sanctimonious clap trap that leads to the decimation of threads due to the interference of those who have to massage their ego by pretending to have friends and influence when it is patently obvious they are legends purely in there own sandals

 

[Pauli11]

If anyone can genuinely help with the original post, I would appreciate it. I have completed one install on a yplan system, and I am nearly there on this one, but some advice would appreciated on my questions above.

 

[stem]

Hot water tank valve has 5 wires, orange to 10, grey to 1, black to 2, blue to 9 and earth to 8
Heating valve 1 (living)has 4 wires, orange to 10, grey to 1, blue to 2, and brown to 5.
Heating valve 2 (beds) has orange to 10, grey to 1, blue to 2 and brown to 7.

OK sounds reasonable.

I have a black cable coming through the wall with red to 10 (on top in the pic), black to 9, and green to earth 8 (could this be the boiler which is located in the garage?)

Probably not, because according to your description of the hot water valve wiring, terminal 9 would appear to be the live supply to the hot water motorised valve. So I suspect it will have more to do with the hot water thermostat and any hot water time control (of which you make no mention) But you need to confirm this.

from the grey sheaths coming down the conduit, there are 2 reds going to 4, a yellow to 5, a red and yellow to 6, and a yellow to 7 , some of these at least are likely to come from the hall and bedroom stats.

To work out what they all do, you need to say what each of the above wires is connected to at both ends. Unfortunately, there is no defined colour code and the wires would be chosen according to the personal preferences of the original installer. It would be foolhardy to guess.

On the heatlink, I am running live to live, and n to neutral from the switch. I am then linking L, 2 and 5 together.
1 and 4 remain unconnected?

Sounds OK

This leaves 3, and 6 to the heatlink.
Im thinking 3 on heatlink goes to 5 on the choc block to meet the brown wire from the living area heating zone valve?

Can't comment on this without knowing where the wires from the living area heating zone room thermostat come in to the wiring centre

I have not located the cylinder thermostat, just the metal valve as described above. I understand 6 on the heatlink needs to connect to the cylinder stat?

Correct, so you need to find it. Also, what controls on on/off times for the hot water. (I assume that the room thermostats are programmable to provide time control for the heating part)

This is the living area thermostat. which of these two wires would be the wires that attach to t1 and t2 on the heatlink for nest 12v power? and what should I do with the third?
View attachment 120755

None of them, until you trace them and remove them completely from the wiring centre, otherwise you could put 230v on your thermostat and blow it up. Once the wires are disconnected from the wiring centre, you can use whatever colour you like, so long as T1 at the heatlink goes only to T1 at the thermostat and T2 at the heatlink goes only to T2 at the thermostat. For the unused third wire just insulate it so that it doesn't cause any short circuits and tuck out of the way.

 

[Pauli11]

Would it be a viable alternative to mount the two heatsinks in place of the Horstmann timer unit thereby not having to mess with the junction box in the airing cupboard?

Here is the wiring diagram for my Horstmann Channelplus XL, Model H37 3 zone programmer.

and the corresponding wiring on the wall plate:

Apart from the L, N and Earth coming in, there are only 3 wires, red to 1 (zone 1 living area common), yellow to 3 (zone 2 bedrooms common) and blue to 5 (hot water).

I will be using 2 Heatsinks. The first will control Zone 1 heating for living area plus HW, and the second will control just zone 2 heating for Bedrooms. Would I be safe then connecting red on 1 above to 3 on Heatsink 1, and blue on 5 above to 6 on heatsink 1? Then for the second zone (bedrooms), yellow on 3 above to 3 on heatsink 2?

Only issue then if thats correct is figuring out how to get 2 extra pairs of wire into this box to provide 12v to the t heating zone stats. (I would prefer they were wall mounted.)

 

[stem]

Great thanks a lot Pauli11

I spend an hour looking at your wiring and replying to you post, and only now do you think to mention that you have a Horstmann Channelplus XL wired in to it.

Yes it would be easier, and now you have posted the wiring diagram for it you have everything, you need.

 

[Pauli11]

Stem, I was typing my last post as you posted your advice. Sorry about that. I presumed all of these systems had a timer unit by default. I also need to locate the cylinder stat to make more sense which I will do later. I will also endeavour to find out what every wire coming into the junction box from outside the airing cupboard is connected to.

 

[Pauli11]

I'm not sure if the second installation option is valid, it would be easier and neater if it was possible, but in retrospect I don't think I will be able to get 4 wires in there for 2 stats. The two links might install easier , but I want to have the two stats in the same place on the wall.

 

[Pauli11]

Done.

And would be more than happy to help anyone in the same predicament.

 

[stem]

Good, well done. I take it you wired it in to the Horstmann and just decommissioned the living room thermostat at the wiring centre. It's much easier and safer for a DIYer to do that.

 

[Pauli11]

I agree but it turned out a non starter for me, it would have been the easier option but I could think of no easy way of running 4 spare wires to the Horstmann timer box (for 2 x Homelinks) to supply 12v to the 2 Nest stats and I wanted them wall mounted in the same place as the old stats.
There weren't enough wires in the timer junction box to disconnect and convert either.

So, it was back to the main junction box in the airing cupboard and a concerted effort to trace all the wiring. What was throwing me was that I couldn't find an obvious cylinder stat, but I knew there had to be one.
So I pulled the instructions for the tank, a Santon PremierPlus 300 ltr unvented. It is delivered pre wired and assembled, and after reading it was clear that the thermostat was actually incorporated in the immersion heater housing.

Once I could see that, it was easy enough to trace the stat comm wire back to the junction box, and a connection to 6 on the Homelink. Then 3 to the brown on the heating valve, 5, N and L took care of itself.
On the 2nd homelink, just N, L and 2 to the bedroom zone valve.
To trace back the stat wiring from the 2 room stats to the junction box, I found it easiest to (with mains power off) join the 2 wires at the stat end, then use a multimeter to run a continuity test. Done the same with the 3 wires on the other stat. Quick connection to the T1 and T2 terminals and I have the Nests wall mounted and powered.

Best tips for beginners from a beginner:
1 Do it all on paper, draw a 10 point choc block ( or whatever matches your junction box)and get some coloured markers. Mark each cable running in to the junction box, then use the coloured markers to indicate what terminal the individual wires go to. If you do it neatly, its easier to decipher what cable belongs to what, i.e. pump, boiler, timer etc. Most cables you will be able to trace back easy enough particularly to the valves, cylinder stat, etc. For me, the cables coming from the wall were for the timer, pump, 2 x stats and boiler. Remember though, ultimately, you are only looking for 2 or maybe 3 cables at best for your homelink connection

2: A multimeter is almost essential. Not expensive, but I don't know how you could trace your thermostat cables back to the junction box without one. Doing a continuity test gives you 100% assurance you have the right cables identified in the junction box.

3: Take your time, study and restudy the junction box, it does get easier to decipher with some thought.

4: If you still need help and advice here, ignore idiots like The Real Pin 5 above who has posts like that all over threads about Nest, and likely elsewhere. Decent guys like Stem will come along and offer assistance.

5: You are entitled to ask questions here, its a DIY forum, and no-one is obliged to answer. But, if ultimately you do get stuck, don't take any risks. I'll always have a go at these things in so far as my understanding takes me. But I know my own limits too.

 

[stem]

OK, thanks. Out of interest, what did you do with the wires that went to the Horstmann that were controlling the Living Area zone and Hot water timing?

 

[Pauli11]

OK, thanks. Out of interest, what did you do with the wires that went to the Horstmann that were controlling the Living Area zone and Hot water timing?

I have removed the Horstmann and left just the wiring block. I have taped up the hole as I am awaiting a blanking plate and at that point I will disconnect wires at the junction box. With the power off, Ill likely do a continuity check back to the junction box. Am I right in saying there is another quick way of doing this by moving one wire at the timer end to another slot at the timer junction?