Central Heating Electrical Wiring - Part 2 - S Plan 

By far the best video on RU-vid explaining s plan wiring . Very helpful .

Exemplary video - Clear, unambiguous commentary combined with great diagrams. I went from being unclear on the operation of my system to understanding the totality after one viewing. This sort of clarity is unfortunately incredibly rare on RU-vid (and elsewhere). It is rare because it is very difficult to make things appear simple and straightforward while covering the subject comprehensively. Well done and thank you.

Thanks JW. My mother had been without central heating for the last 2days. Today the heating engineer didn’t tun up. Your videos helped me when I was training to become an electrician. And they have proved invaluable again. After searching in vain I came across this video and was able diagnose the problem in minutes. And restore heating. Thank you again John. Please keep making videos.

Thanks John, you helped me to realise that the three cables entering my programmer box were the three-core timer-power cable, the power-out cable going to the boiler, and a three-core cable consisting of neutral and yellow cores from the room thermostat, and a red core from the cylinder thermostat; rather than the advice that I had received from the electrician who had fitted the previous programmer, that they were a power cable, a cable from the room thermostat and a cable from the cylinder thermostat. No wonder I kept blowing fuses as I replaced the old timer with one which would control the water and the central heating separately. Oh what fun I had as I vaporised the neutral core on the power-out cable! What pretty flashes it made! I was so happy that I only burned out the switch on the fused-spur! Thanks once again for such clear expositions of all things electrical.

Great video, John. Liked the way you built up the diagrams and also the simplified versions to show when various parts of the wiring were live.

Many Thanks John for saving me a lot of time trying to work out the wiring plan for my 40 year old boiler.

If only college days were this clear and concise. Fantastic video !!! Thanks you so much. I can now stop pulling out what hair I've left..

Excellent and very well explained as always. Helped my fix a overrunning pump issue - turned out to be a faulty valve exactly as described in the video.

thank god for you john...god knows where wed be without you, clarity, understanding and an ability to communicate/teach

Exceptional clarity, and extremely useful video. Now I understand how my system actually works, and in great detail, so thank you.

8 years ago vid still doing extremely well in terms of illustration and logic, as well as the fault finding tips, brilliant.

Thanks as always for providing these guides. They are perfect, unlike every professionally or DIY system that i encounter each time I move house. I spend a day wondering how on earth any of it works, draft countless schematics, then remember your channel and suddenly I am able to understand the bodge before me and rework so it's closer to standard. This time we have 30 year old house (was the show house) where mains and the boiler wires start at the programmer and the room thermostat is fitted to it too. Thanks again John for preparing, producing and sharing. Very much appreciated.

Been looking for a simple explanation of these systems for forty years ! Very well done.

Sorting out problems with an inherited system. this was invaluable. Very clear. thank you

Thanks for taking the time to create this John. Clearest explanation I've heard, with good graphics too! Thanks

Excellent video. I'm new to the industry and currently on intense training course to be a gas safety engineer. Did this same topic in class yesterday and couldn't get it round my head. This video has helped my understanding greatly and the way John does the presentation is excellent and his calm voice helps. His videos will be my reference during my course. great job!

Great Video, very well explained. Really liked the way you explained the reason why the external motor remains on for a while before going off. Excellent. Well Done JW

Removing neutral and earth wires made this very easy to understand - great video.

Best video I have seen on this, by far. I only wish you had produced it before last winter when my 3 way mid position valve decided to go on strike. I know that particular valve is just a combination of the two you have shown but working out how it worked with the other components and what the fault was caused me no end of problems. It was a faulty actuator head on the valve (only a year old) . The symptoms were no central heating unless the tank thermostat wanted the tank heating.

Excellent - just how a video should be - clear, concise and no unnecessary information.

Never fails to explain it extremely well. I nominate John for an OBE. Can I get a second?

Very well explained indeed. Spent most of my life doing electricals and I found this excellent. Thank you for your time.

Brilliant breakdown of the S plan in full detail 👏👏👏👏👏👏

Great video, going in for my am2 in a month and wanted to know how the wiring all works instead of just following a diagram, your video is perfect to learn from as the step by step really helps, massive well done

Thanks for the video John, I had been struggling with this for a while, cheers.

Amazing explanation John. Your electrical signal flow graphics made things really simple to understand. Much appreciated.

The definitive video/playlist on heating control wiring .

Well done John, again you saved my life, Had a Cowboy plumbing moving my boiler but after he wired it did not work, Only to find he had his own way of wiring it, So I pulled all down and followed your Video ,AND ALL WORKS, Thank you again for the Video.

Really, really helpful for documenting the configuration and diagnosing problems on my central heating system. Thank you so much!

Great video explaining everything in simple steps to build up the full picture. Removing some of the common wiring to show how the system works and common faults was very useful. The clarity, simple plain English explanation and build up, one of the best videos I've come across. Hope you can update it with new hive connections on combi and system boilers.

Excellent , I've just moved house and this is invaluable....Many Thanks

Great video - explains everything I need to know for my heating controls. Thanks.

Brilliant and very clear, as an electrician I had never worked on central heating wiring, this did validate the fault diagnosis that I had made for my own house.

Great video,very clear and easy to follow, I used it to build a 2 zone central heating, and megaflow hot water system as a separate zone, in my new but old house👍🏻😊👍🏻 cheers JW

Best Description I have seen, Thank You

Thank you. Your videos are not only my guilty pleasure. .. but very educational for me.

I do like your videos ive learnt alot from you information is plain and straightforward.

An excellent video, very clear to understand and exactly what I was looking for. Thank you so much for taking the time to make the video and share it.

Hi John, I am learning electrical insulation and found your videos highly useful. In regards to central heating wiring system, if I could kindly ask you to produce newer video. Because I found your recent works much more easier to understand. Love you a lot and thanks for making difference.

Thanks John, I fitted my system many years ago now wanted to replace the cylinder thermostat . Your vidio and explanation refreshed my memory regarding what wire fed what as this new themostat only has three teminals.

awesome video John, thank you

Well put together. Impressed by drawings etc.. Good job

Thank you John, probably far more information here than I needed to know but like others visited to check programmer compatibility with a Nest or Hive. Cheers for an excellent video

John, Thanks for another amazing video, I have been following your channel for a long time and love your videos, I have just realised how easy it is now going to be for me to automate my central heating system using Arduino and make it work with my planned home automation system that I am currently planning to build. Thanks so much

Fantastic as always John.

John. A very informative video. Part of my tool kit now. Many thanks👍

The best explaination and drawing on you tube. Thank you so much

Excellent vid. Just helped me get my Nest Learning Thermostats installed.

Brilliant video for newly qualified engineers. Thanks

Brilliant video and so easy to follow I have a great idea of how a s plan works 👍👍 can't wait to see more

Many thanks JW. Such a great logical explanation in a well illustrated & timely manner. Just brilliant.

Great video John, really informative and you get the information across clearly. Spot on!

Excellent video, very well explained. Thank you

Great mentoring, thank you for taking the time to educate us meer mortals... very useful video, made clear with accurate instruction

Excellent video, very clear, and to the point, thank you

John...That was excellent.......I know exactly where to check now.....My central heating was not switching off with the timer removed so it looks like heating control switch that is faulty.......Many Thanks.....

Great video with really clear explanation. Thank you for taking time to make it!

clearest explanation I have seen of the 'S' plan.

Total pro. Very clearly spoken and described at steady pace. Tx a mil

Very well explained, thank you, John from sunny Devon UK

This video is better, much more understandable thanks to the brilliant diagrams, excellent work John, bit lost before watching this video good work, thank you.

Your videos are amazing. Thank you.

Massive help in understanding this before I do my AM2 exam, I never touch heating systems

Very clear explanation - a great video!

Thats way easier to work on. Thanks for taking the time to post. Subbed

Fantastically helpful video John, it's helped me diagnose a failed Honeywell valve on the central heating system :)

Amazing video you got a great talent after watching this i understand more clearly

Your a legend thank you…always struggled with heating controls

Terrific tutorial - many thanks.

Explaining things simply is an art form!!

Very clear & detailed video, thanks you for the explanation.👍🏼

You never fail jw excellent display.

This is great, explains why pins 1 & 2 are unconnected in my programmer! Annoyingly, I have a 5 & 6 which go to my thermostat, so if I want to put on an internet programmer, I need to change the plate.

Brilliant diagrams really helpful

Great informative video :D

Great information. Thanks for publishing this it's a great explanation of how a heating system works.

Many many thanks for a well presented easy to understand video. 👍👍

Very good explanation. Well done you!.

great video and really explains it very well

Great jacket! (also love these videos, thanks)

Best explanation I've seen.

Brilliant. Thank you. Very clear

Well explained JW thanks

Very good video. Easy to follow and highly informative. John is a good narrator too and explains things well. Thank you. I do believe however there is a small error though at approx 15:40 minutes of the video where John states that "if hot water valve or both are open, the switches inside will be OPEN to turn on the boiler via terminal 10" The switches inside will actually be CLOSED to do this - not Open

Such a brilliant explanation.cheers

Very helpful thank you, how do you adapt wiring to change to wireless thermostat and controller e.g. Drayton MiGenie?

Great video took me two watches but finally got it has been bothering me for a while

Thank you for this video. It saved me a lot of heart ache. Had a faulty valve which kept the boiler on and when I went to replace it. It turned out the person who had done the installation had put the two thermostat in series on the heating system and none for the hot water 😳

Fantastic video. Thank you.

Very well presented.

Excellent. Crystal clear.

Excellent video. Thanks.

Thank you so much for this video 🙏

The best video on RU-vid!!!!

Best DIY videos start like this "minames Allen Hart" and "Hello, I'm JW"

Superb video, thank you!

Very good explanation, thanks

Excellent, very very clear, thank you

Great video thanks for the help

great video John. A+