How to install Nest thermostat (UK) on a Y plan - system with hot water cylinder & 3 port valve 

for schematics click here: www.urbanplumbers.co.uk/nest-thermostat-installation-schematics-y-plan-system-with-hot-water-cylinder-and-3-port-mid-position-valve/

Great video! I’m a fairly competent diy plumber/electrician but struggling with over complex explanations of installing nest. You sir absolutely nailed it, can’t thank you enough for the clear professional explanation. I feel I can now easily do this myself

Well done the first person to explain the y plan set-up fully!!

Still so useful! I just installed the Nest in my new house and everything was very straightforward (for a novice) purely because of the clarity of explanations and step-by-step approach from this video. Thank you!!

I’m a retired plumber with electrical experience and congratulate you on a great video, keep up this standard of educational videos

Thanks for this video, gave me the confidence to complete my install without issue! Helpful after install tips, if your hot water is always on after install and you cant figure out why, go to Settings> Equipment> Bacteria Prevention and disable this at least temporarily. It runs because the system has no record of the last time the water was heated and as the name suggests runs to prevent bacteria build up. (You may want to enable this again later!) If you find your heating turning on seemingly at random before your scheduled time, go to Settings> Nest Sense> True Radiant and turn off. Hopefully someone scrolls through 268 comments and finds this helpful!

I’m an electrician with 40 years experience. Your video is superb. Well done 👍

An excellent tutorial. It exactly matched the setup I had to update and allowed me to complete a Nest installation without any problems. My initial horror of seeing the rats nest of wiring in the main junction box was totally calmed when you explained the step by step transfer of connections from the original controller to the Nest. Brilliant!

I have just stripped and re-wired my entire system with Y valve. All the previous plumbers just messed it up. Thanks to your schematics and video, I did it myself, and now all 3 possible states work perfectly.

What a brilliant teacher! Loved the professionalism and yet ...so clear and easy to understand. Thank you

Cheers for the video. Just installed my Nest now and all seems to be working well. Certainly couldn’t have done it without your tuition. Double thumbs up!

You are a genius my friend! Your excellent video just helped me install a new Nest system which I decided to do myself after chasing several plumbers for quotes but nobody came back to me. Thank you!

Best video for a Y plan. After watching this video, got the courage to install it directly in the airing cupboard which meant I could use the existing wiring to power the nest thermostat from heat link. Having the wiring diagram for the wiring centre helped. Also during set up, there was no option for regular boiler, realise have to choose system boiler. Had to rest the thermostat and do it again. Cheers

This was so helpful. My new house has Y plan heating and it's a nightmare to work out what's what. Following this I was done in less than an hour. Much Appreciated!

Thanks for that video - I just did my install on an house with old coloured wiring, a rats nest of a wiring centre with lots of sheaths over wires, a circuit breaker, 4 wired t-stat and an oil boiler and everything seems to be working fine. The wife is happy so job done !

This video was amazingly helpful. I managed to successfully fit my Nest using this video alone. Thanks so much.

Thank you so much. Huge help!! I'm no expert in this area, and I've always been confused with how my system actually works. Asked a few plumbers who have done work on it in the past and none of them broke it down like this. I didn't even know it was called Y plan!!

Amazing video!! You actually taught me a huge amount here! Thanks so much for posting. I had no idea about S or Y plan heating systems before this.

You create some outstanding videos with wit honesty and clarity. Thank you. This one was particular helpful fitting a Nest 3 to my old Y plan system I installed 30 years ago. The boiler just upgraded to Greenstar Ri by a registered Gas engineer, sadly a poor job but I have my warranty and can now bring up to an acceptable standard. I wish you lived nearer I’m too old for this now, don’t suppose you have a clone that lives up north.

This was the perfect guide to set up my nest, changed it from a hive set up. Wiring centre is spaghetti junction but managed to figure it out. Thanks!

Just echoing some other comments this was by far the most complete and helpful video, got mine up and running after watching this, thanks

Such a great video. I've come on here for some trouble shooting at the last points about timing between testing hot water and heating is really useful. Many thanks will look forward to more videos

Brilliant video. Helped me to fit my Nest 3 without any problems.

this video is pure gold. Thank you for such detail !

Incredibly clear and well made video. Love the camera permission reaction :)

Excellent video, helped to make installing my nest thermostat easy, thanks.

*Works as expected **Fastly.Cool*

Thank you for this. I've been wondering whether to install a smart system. Because I live in a modern house which is very well insulated, there is very little financial advantage in doing so because it would probably take 4 or 5 years for it to pay for itself, so my only consideration is to save energy for future generations. I designed and installed a central heating (Y plan) system about 30 years ago when I was in my 20s (before computers, so I had to do all of the heat-loss calculations on large sheets of paper). I live in a different house now, but with the same setup of heating & hot water, so I'm okay around this system. It has been a long time since I installed that system, but I remember the basics. Your video confirms that I remember enough to have confidence, and it prompted me to recall the bits I had probably forgotten. There is one thing that bugs me about the Nest system, and that is why the heatlink cannot simply fit directly onto an old programmer's backplate (even if some slight re-wiring is needed). Furthermore, now that the old programmer will be redundant, why doesn't the heatlink use the same screw holes? I only wonder because my programmer is mounted on kitchen tiles and I'm not sure there is enough wiring behind the tiles that I can pull through without extending it without using another unsightly junction box). I figure I could mount another metal backplate, or a plywood square, but it feels unnecessary. I figure I will get my head around it eventually.

Very clear video Urban Plumbers, well done.

What I wouldn't give for your skill and knowledge, then finally I could fix my mess of a central heating system 😪

This is the very best tutorial for this topic that I have come across. Thank you.

I DID IT AND IT WORKS. Thank you so much for the video. You managed to save me a small fortune

Thank you so much!! I've successfully installed my Nest thermostat thank you and this video!!

Your brilliant video has made my installation straight forward, thank you.

Excellent straight forward video.

Thank you very much for such a clear and straight forward explanation of a y plan installation with nest heat link. I wonder if anyone can offer me a little help though. Rather than a boiler, we have a geothermal system, with the geothermal heating loop switching between the radiator heating loop or to the hot water storage cylinder via the valve. The hot water cylinder has its own thermostat of course, but also has a separate immersion heater. This separate immersion heater provides backup if the geothermal system fails, but a can also boost hot water heating at a rate above what can be supplied by the geothermal heat exchanger. I believe it’s possible to also integrate the hot water cylinder independent immersion heater into the nest heat link and configure nest such that base water heating can be by geothermal using a schedule, with the immersion heater being called upon to provide top up heat if the geothermal system cannot reach the hot water cylinder thermostat temperature set point. Can anyone provide guidance on how the heat link y plan wiring diagram needs to change to integrate the HW cylinder separate immersion heater please. Any guidance on configuring nest to primarily take HW supply from the geothermal heat exchanger in a HW schedule and supplement this with the immersion heater if necessary to reach cylinder temp would be really appreciated. Thanks, Jason

Thank you helped alot figuring out where me and my plumber were going wrong!

Thank you, finally a layout that seems to work with mine. Been struggling on and off for a while now. New subscriber and liked :-)

Again, great video and great explanation, very clear information. Thank you

Very good and clear. I am now prepared to commit to nest. Thanks.

You are a life saver!!! The best instruction video bar far. Thank you so much 😘

You are an excellent teacher, thank you.

Cant stress how much this helped!

Excellent video, well explained and demonstrated.. probably the best explanation I've seen!! 👍

What a through informative intelligently delivered video :) thank you ever so much

Best explained breakdown on here.

Your a very thoughtful individual thank you.

Good video, did my first fit on a y plan today, helped me no end, thanks

Best video ive seen on this subject..thanks.

Czesc! That was absolutely brilliant! I have a Y Plan CHS with the Junction Box and have been trawling thru Videos and forums looking for a clear and concise process to Self-install NEST on my CH and the advice is full of confusion and lots of 'plumber speak' that is difficult to understand - even your Schematics is idiot Proof!! - buying the NEST Today on a Black Friday deal and will have this installed by the Weekend, you've made this look so easy - Thank You!

Great video and clear instructions, I followed and - it all works!! Thankyou so much 👍

Thanks I found this perfect to help me do a self installation.

This video is a freaking god send. Thank you!

Great video. Super helpful. Thanks for making it!

Thank you very much, this really helped me fit the thermostat, great video. I made 2 mistakes which I have rectified, maybe this will help someone else. When you measure across T1 and T2 looking for 12V, make sure your multimeter is on DC not AC, otherwise you get a false reading (This caused me hours of head scratching). After fitting, there was no option on the Nest Thermostat or the App to control hot water. To solve this, you need to go into the settings of the thermostat, then click on Equipment, then Pro Setup, then select System Boiler.

Thank you very comprehensive video

Well done . A great video

Brilliant made the job a lot easier 👍

A very easy to understand video.

Really helpful. Thanks.

It would be great to see you do a how to video on converting an old y-plan 3-port valve, controller, mains thermostat and cylinder stat. My aim is to basically gut the old wiring and replace it with VR66/02 and VRC720. Thank you!

Very nicely put together video. Extremely clear and easy to follow and as I have the exact same setup. It's easy to translate it across. One question. What are the ends you have on your wires that keep them crimped so neatly.

Excellent video!!

dzięki super przydatny poradnik. Pozdrawiam

You are a total superstar, thank you

very infomative a question though if you set up a nest /hive for y system and change to a combi system, can you use same nest / hive unit or do you need an upgrade on either

Very well explained

Great video - thanks for taking to time to record and share! I’m just about getting my head around the wiring now. One question I had was - I wish to utilise my room stat wiring in my hallway to mount the nest stat to the wall. The cable (3 core & E) appears to run directly up to my wiring centre in the airing cupboard. Do I need to install the nest heat link inside the airing cupboard instead of where the programmer is by the boiler in order to utilise the stat wiring? And if yes do I essentially just disconnect and make through any wires that require it form the existing programmer. (Located underneath my boiler in the utility room)

Great video, tomorrow I will wire my new Nest up using your information. I also have an immersion heater that I had hoped the nest could turn on during the night when our electric is only 5p per kw, I figured this would be cheaper than using oil currently over 90p per litre. Is it going to be possible or should I be buying a separate time to control it?

Quality mate 💪

Great video.

Hi really like your videos.if you intend on using the stand for the nest and not the existing room stat.what do you have to do with the thermostat connections ?

Super star, you are!!!!!!! Big thanks

Thank you very much for making all those tasks simple! I am trying to add nest to my home now and in my programmer i don’t have (wire 1 hot water off) what should i do in thais case?

Awesome..! Super informative..♡

Amazing video. I watched at least 10 different videos but only you helped me to understand which cables :) I have one question. I have very old timer who controls extra electric heater installed in my tank. I don't know how and when this stars but when my gas boiler wasn't working I still had hot water automatically. Can I control this heater by nest thermostat? Which is the best way? Thanks

Amazing video. Just what I needed. Thanks. Is it possible to have the Nest wired in place on the old room thermostat and the portable base? So I can have the thermostat on the wall and take it off when I want it in a different room? Or will wiring the thermostat into the boiler stop the capabilities of the portable base? Thanks. Ben.

Fantastic the best explanation you not D o d but you are G O D thanks a lot from India

Awesome video thanks! I am thinking about doing this myself at our new house. However, the wiring centre is in with the hot water cylinder and the heating control unit is downstairs in the kitchen. So to trace the thermostat wires from the wiring centre through the walls could get messy! Is the better solution just to disconnect the heating control unit and wire the nest heat link in the hot water closet? Thanks!

very clear and easy to follow thank you, do you have a video for y plan using nest on opentherm with a modern boiler

I followed your instructions and its great. The only issue i have is my old thermostat has 3 wires. My nest is not firing up the boiler when only heating is required. Boiler is fired up when hot water is on and heating turns on. The 3rd connection of the thermostat… is this what would fire up the boiler? Do i connect this to “Heat On” wiring?

Great Video, Many thanks Super helpful & informative Installed the nest 3 today with almost no issues ( apart from forgetting to tighten the 12V feed screws lol) All test seem to have worked Any chance of Y plan open therm nest video?

what do you do with the thermostat if you art going to put the nest there but its sitl lon the wall otehr than set it perminantly on? and also if you cant find the wiring junction only the programmers old box?

If I had an interest in plumbing, I'm sure I'd find this video very useful!

Hi - great video btw, very informative. I have a question...if I’m going to plug the nest thermostat into the mains via the stand is the installation complete once I’ve wired up the heat link and added the live jumper wires? Thanks

Hi. Great video, however I don’t have either. We have a combi boiler?

Great video, great help. However I only have one brown wire from the control panel? Where should I put the grey and black?

Tried to install generation three onto a Y PLAN system. Heat link light solid green thermostat connected ok. But boiler doesn’t seem to recognise heat link and is continuously firing. Checked all the wiring every thing is where it’s supposed to be . Honey well wiring station was working fine with old programmer and thermostat . I made sure I move ch on over to number 5 -white cable for 3port. Can’t work out what’s wrong.

Had anew Baxi 800 system boiler, new 3 port valve, new CYL Thermostat, and New Nest. Followed all your wiring downloaded diagram and cannot get boiler to fire up, I.e. no 240v to orange/boiler live. Changed the Nest Heat Link. Only way to get 240v to boiler live is by turning up the Cyl Thermostat and turning on HW boost on nest. 27v on orange/boiler live when no HW or Heating. Thanks for any help

Excellent, bit I have a question.... assuming you dont want to put the nest at the site of the old thermostat, what should we do? Just twist the 2 wires together???

Thank you for this and other videos. I have a question. Is it possible to have another thermostat in another area of the house powered using the USB power without the use of a second heat link?

My main control unit is upstairs next to hot water tank, programer is in kitchen next to boiler and room thermostat is in hallway. I would put heat link in kitchen next to the boiler and old programmer and connect up as explained, got that. I then get stuck as T1 and T2 currently go from hallway to main control unit same as your demonstration but how do I then get them to go from hallway to heat link in kitchen?

Very good brilliant

I don't seem to have a "HW off" cable connected in my existing thermostat. This makes sense because the hot water has always come on (incorrectly) with the heating for some reason. However, it doesn't transfer to the Nest - there is continuity between 1 and 2 and 2 and 3 whether the heating is on or off, resulting in the heating not coming on at all. Any ideas? p.s. it is definitely a Y-plan. I seem to have an NS5 actuator but only 3 wires coming out of it.

Hi, great video. I've installed nest from a honeywell 42005748 junction box which was connected to LP522 drayton programmer. Hot water is working fine but heating is not. The wire for CH on which was connected to the old programmer i have in terminal 3 on the nest. It does not appear however to switch the 3 port valve to heating and not hot water, so boiler does not fire when heating is called from nest, but if i call for hot water then the boiler fires and heats tank for hot water only. I have all the jumps as per instructions but wondering if i've connected the wrong wire from the junction box for switching the 3 port valve so that it feeds the radiators?

Amazing channel and video. Where does the wire for the central heating pump go? I seem to have one going back to the old controller...

Like your content Could you please help me work out what problem i have Cdi 30 system boiler on y plan with Cyl and three port valve, with removed F& E as converted to sealed system I get rads heating when I switch HW on with CH off 3 port ok and no reverse circulation on rads

My existing programmer does not have a wire for hot water off. I have a 3 port valve. Can I still install a Nest.

One question if I may? On the same system how do I turn the temp of my hot water down please? It really is boiling.

Brilliant instructions, thanks. I got one problem and hope anyone can help. My boiler kicks off for hot water when cylinder thermostat is set below desired temperature , and then I have to force motorised valve to feed hot water. The motorised valve is working fine, I even replaced it with a new one and can see it switches between hot water and central heating correctly but the boiler only kicks off when cylinder thermostat is below desired temperature, let’s say zero or 10 degrees