Central Heating Electrical Wiring - Part 3 - Y Plan

[@lexmarkakis3087]

John Ward is so under rated this guy is giving out gold dust thank you mate 🙏🏻

[@garyharrisonuk]

Probably the best, informative, well presented, KZbin video I have ever watched. Great work John, thank you for taking the time to create and upload.

[@markthomasson5077]

Agreed

[@lifter98]

A masterful explanation of a complex process, clearly and concisely delivered with no stuttering or pausing for thought.

[@martinsmith9303]

Just watched this as I've got to sort out a few problems on a Y plan heating system . Very very good explanation with no confusing fancy trade talk. As with most things if you understand what it should be doing and exactly how it works, it's so simple so accurately diagnose the fault like a proper engineer and not a guess engineer. Great video John , Many thanks

[@TGODHUMMELS]

That moment when your college course fails you and you rely on John Ward to teach you how to pass half of your AM2 Exam.... Cheers mate, you are helping people every day with your attention to detail in every video you make. keep it going!

[@aspudkicker]

I guess the course thats being provided to you is a bit pants then. Part of our c&g L3 plumbing course in center practical test was to wire up a y plan system, and then to pipe up a unvented cylinder with a 2 zone heating system to a combi boiler, and then wire it up appropriately. Fortunately the college provided wiring diagrams to work from. I asked the tutor why connect a unvented cyl to a combi, the answer was so that there was instantaneous water near the combi for example in a laundry room, but if the cylinder was next to the bathroom some distance from the combi, this then eliminates a leg of cold water, saves the customer running a pipe full of domestic water off, therefore not wasting water and leaving a pipe full of hot water afterwards. Doing this means you meet the water regs section of not wasting water and part L of the building regs. The other method of acheveing the same outcome of little to no dhw wasted, would be to have a fully pumped dhw system similar to hotels. I have seen this type of pumped circulating dhw system only 3 times in a domestic situation. Y and S plan wiring diagrams are available to download, I keep copies of them in my van. But most of my work on y and s plans is replacement of parts. The easiest method is to replace with like for like, as some manufacturers use different colours especially with zone valves, most do supply a conversion chart with their parts. If your wondering why I'm watching these video's, the answer is I'm looking to change career paths from gas engineering/plumbing to electrician, I've already completed the domestic electrical installers course. Summer time I'm planning to sit the 17th edition exam, and if all goes well, next year return to college to start the c&g electrical course, (returning to college will be interesting, as I'm likely to be a similar age or older then the tutor).

[@LC-qi5ff]

aspudkicker why are you looking to change career paths, if you don’t mind my asking?

[@johnnicholas978]

This guy is brilliant...I'm 64 the money and more important....the TIME...IV spent on these courses over the years. Ohhhhhh...I wish I had access to John's brain years ago....his very good at it...

[@AB-oc5lj]

Have watched this five times now and learn something new every time. Everything about this video from content to presentation is top drawer! Brilliant diagrams too. I find that I am watching more and more of your videos. Keep up the good work John.

[@marclindup1434]

John thank you very much for this. I don’t think my hot water and central heating have ever worked properly. Took it apart and re-wired as your drawing and it all looks to be great. Thanks again. Love your channel.

[@irelmo69]

This has helped me understand my heating system and allowed me to replace the valve motor and pump. Amazingly clear explanation of it all. Next will be to re-wire as it is a really big mess!

[@markkemish5990]

Thank you so much for creating this video, using this video I was able to fit a new Hive system, and I finally have correctly working heating and hot water . The previous system was suffering from a broken room thermostat, but more importantly thanks to your video I realised that the engineer had wired the previous system incorrectly. I would have been lost without your help. thank you.

[@djmiliboy]

When you fit the Hive system, after disconnecting your old thermostat lines from the junction box, did you move line 4 from the programmer to line 5 in the junction box?

[@petergregory4890]

This was invluable in my 'home install' of a Hive system and also upskilled my knowledge of how my heating system works. I agree with the comments below, very clear and easy to understand video, keep up the great work JW!!

[@Craig-Mitchell]

The simplest and easiest to follow explanation 👍🏻

[@Guillelgas]

I've bought a new house a noticed the Heating only option was not working (could only get heating when hot water was on and heating the cilinder). Thanks to this video (among other info online but this mainly) I pass from not knowing how my system works fully to indeed identifying the problem and solve it (replacing the 3-way valve actuator). Thank you very much for this free content with such a high quality that is unbelievable !

[@fredrickwelch5678]

One of the most underrated channels on KZbin

[@jonathanhaslam6281]

This video made soo much sense compared to others, love the drawing and the firm and ver clear to understand and that from someone dyslexic. Thanks John a true engineer right here! sub, liked, and shared!

[@Ian-yx1de]

Great video John. Didn't think my system had been wired correctly- it linked HW&CH together despite having all the hardware to be able to seperate CH only. I'd never bothered with the issue till the price of gas rocketed upwards . Masterful explanations for a non-engineer such as I, you enabled me to re-wire completely and sort it. Thanks

[@gerryabbott]

Many thanks for the video, and the layout diagrams. Just implemented the 'S' plan with 2 two port valves. Had to split the wiring between the boiler room, and the hot press where the cylinder was. Ran 6 core cable between them. Worked a treat. Should have done it years ago.

[@karlellis3593]

Excellent explanation of the Y plan wiring helped me to sort out an issue on my system when fitting a Nest thermostat, the level of detail and explanation are the best on the internet. Keep up the good work. Thankyou

[@markhoward52]

This series of videos has been so helpful to me. I have an assessment coming up. Clear and concise. Thank-you John for putting them together. Excellent !

[@whitefields5595]

JW, thanks for going to the trouble to make this. There is a lot of thought and production time in this. It is much better than the plumber’s vids. This step-by-step approach helped me diagnose a faulty programmer, having started out thinking it was the 3 port valve. Your description helped me put in some jumper wires to bypass the programmer to verify it was indeed at fault before I went to Screwfix for a new one. All too often tradesmen just fit new parts until the problem goes away rather than do the diagnosis first. I stripped down the old Drayton LP522 programmer and found the CH relay was OK, but not energising, but could not go any deeper because of the ATMEGA 169P microprocessor driving it. I've posted the programmer to you to see if you can fix the output stage of the CH relay driver for another vid.

[@SwichMad]

Exceptionally well explained - helped me understand my heating system without any prior knowledge of heating systems wiring. WIFI thermostat inbound 😊

[@alax5953]

Your video just saved me a plumber callout :) the switch in the actuator wasn't working, meaning central heating on its own wouldn't work, since the switch didn't trigger the boiler and pump to come on. If i ever meet you i owe you some drinks!!!

[@Carl-re6zb]

Hi J.W.. as a heating /plumbing engineer with no love for electrics.. (my colleague does all the electrics) , i have realised how necessary this aspect of the heating game is when it comes to fault finding. Because of your clear video instructions, i have not only begun to understand this but I also quiet enjoy this new found element of learning. Thank you sir and keep up the good work.

[@jezm1703]

Very clear and precise explanation. Wiring diagram animation is excellent. Thank you.

[@davidlenton2366]

Brilliant explanation. It really helps when you can understand what the jumble of wires in the airing cupboard is doing (or not doing my case). Thanks

[@fardellp]

Surely in this day and age a simple logic circuit would do all this. Excellent description.

[@alaneccleston4213]

Just watched your videos on central heating Y plans. Really great explanation and graphics you are to be congratulated. Keep up the good work.

[@phjones01]

Absolutely superb breakdown of how this works.

[@warneronline]

Your videos set a very high standard. As a relatively new heating engineer, most of this electrical information presented here would take far longer to achieve in the field and certainly not covered at this level on my gas training course.

[@laernulienlaernulienlaernu8953]

I love all your videos, whenever I can't sleep just a few minutes of your dull, monotone ramblings is enough to send me straight to sleep.

[@darkbyte2005]

Brilliant series jw, thanks for spending time putting all the parts and a great presentation

[@tomroland2315]

Excellent presentation. Feel like I'm back with the CEGB in my training days..

[@mean600machine]

Thank you for the 3 videos I was able to trace the wires and identify the error in my system. Great clear video

[@cabbagesrockmywor]

Very helpful explanation, much better than the black and white smeared version in my boiler manual. Thank you!

[@bottles5736]

Absolutely amazing channel! Good work!! I’m sure many people appreciate it, I know I do! Thanks

[@MatheusSouza-dp8lw]

Thank you sir, you just saved me around £200 quid! You make DYI easy!!

[@Ray-ki6fs]

I’ve found this very interesting as I’m about to change my 3 port valve. Before I do I thought I’d take a look at the wiring centre and have a look at the wiring. Now it was originally done some 26 years ago and it sort of resembles the wiring you describe, but whoever wired it when the house was built never followed this plan, for starters they used a 10 way terminal block, leaving no.10 spare. They wired all the earths to terminal 1, with the blue and white reversed on the terminal block and orange on terminal 5. The only wire on the terminal block to be on it’s correct terminal is Grey on 7. It looks like I’ll be replacing like for like, but I guess 26 years ago there wasn’t a standard diagram for installers to follow, or the installer who put mine together was a maverick!

[@jwflame]

There are many different wiring arrangements - some are more common than others due to being available in various books and training materials. Doesn't make any difference electrically, the main thing is to ensure a diagram is provided that identifies all of the terminals.

[@TheBriggsyboy]

Hi this video was fantastic, thank you so much for providing such a clear detailed explanation I just used this to diagnose my heating problem. I found that the Micro switch was not making on the mid valve and would only provide heating when the water was on. Secondly I really enjoyed learning about a heating system as well.

[@davidtomlinson2782]

Thank you very much for this clear and complete explanation. The animated wiring illustrations are brilliant.

[@brianoneill350]

Thank you JW for this and sharing such a crisp and concise mind 👍

[@Chad-ski]

Very interesting and well explained video. Importantly, JW even tells you, if you’re diagnosing a problem, that the only 3 things likely to go wrong are the 2 stats or the 3 port valve 😁

[@quinsee66]

Very well explained John I'm an electrician and love your videos

[@jjmbe]

Another helpful and clear video from John Ward. My only suggestion would be on the diagrams to colour the lines to the 3 port valve to match the wire colours on the valve.

[@BoomBoxDeluxe]

Ace. :-) We have a Y-plan here, and the three-port valve is a SwitchMaster, as is the cylinder thermostat and the room thermostat downstairs. The pump is a Grundfos, the boiler is a Myson HouseWarmer Elegant II, and is in the front room (back-boiler arrangement) I do know that Horstmann also do programmers and the 3-port device, as well as Honeywell. Another name in heating controls is Satchwell. We had one of those around our previous house controlling a gas-fired hot-air system (Thorn-Sugg) and what I didn't like about that controller is the POXY thing had the room temperature marked in Farenheit. The only thing I knew: Spin it to 60, and the heating fires up. :D Thanxx for showing, -BoomBoxDeluxe. _12th November 2015, 01.01_

[@fargogemini694]

I still refer back to this video seven years on John could not have explained this better top man

[@richharris9464]

Fantastic video, I was able to trouble shoot a problem with the boiler not firing up when the CH only. 3-way valve not providing power. Many thanks.

[@malidogal6950]

Thank you for wonderful explanation , I got a question about underfloor heating and radiation if it’s possible to operate with one zone valve if it’s ok how is the Wiring? Thankyou

[@jwflame]

Y plan can't be used with underfloor heating. You need separate 2 port valves for each zone, so one for the radiators, one for the underfloor, one for hot water cylinder if you have one.

[@dkek383]

Thanks for the video, it helped me make sense of my wiring when I fitted a Tado smart thermostat. The arrangement seems a bit convoluted, especially having mains voltage thermostats, I was expecting a central controller with everything connected into it. Presumably it was done this way in the age of electromechanical controls and has just stayed the same ti maintain compatibility.

[@Marco-ek8wu]

Great video, just wired up a hive and a green star ri boiler. S plan set up and followed the wiring diagram to the letter but I’m getting hot radiators when the hot water is switched on. Triple checked all my wiring and can’t see what’s wrong. Even replaced the Honeywell valve to be in the safe side. Any advice would be appreciated

[@gonzalomartinez1630]

Hi John, thank you so much for your videos, they are a great help, I did not get this in my gas training.

[@TheYusra2008]

Hi John Thanks for the videos they are very helpful. Communual heating flow and return pipes feeding the radiators and cylinder in the flat there is mid position or 3 port valve,cylinder stat,wiring centre,programmer and room thermostat we set the cylinder stat 65 degrees but at the kitchen hot tap is more than 65. What would be the cause and how can we avoid hot water getting too hot?

[@jwflame]

Y plan can't be used with communal heating systems - the valve default position is open to hot water, and in a normal system the boiler is switched off when hot water isn't required. On a communal system the supply pipes will always be hot, and the as the valve is open, the cylinder will be heated 24/7 regardless of any thermostat.

[@peterryan7827]

Many thanks, great video,and very well explained, can I just ask if your not replacing one item say a motorized valve, and you have not got a Honeywell, is it generally accepted among manufacturers that the same colored wiring is standard so you cannot mix up the connections when following this diagram.

[@jwflame]

Yes, most manufacturers used the same colours.

[@johnmarshall2660]

Very interesting video ... I have been trying to get my head around the wiring for the Honeywell V4073S valve but I want to use with 2 x Room thermostats i.e i upstairs and 1 downstairs ... so when heating on I want upstairs to turn off at say 19 deg and downstairs to keep on till say 21 deg ... so could I just use the second room thermostat instead of the Cylinder thermostat ... reason for this idea is I live upstairs but during the daytime I run a childminding business downstairs... so dont want upstairs on as much ... Regards John

[@jwflame]

It could probably be done with a mid position valve, however it will be far easier to use separate 2 port valves for each zone, you can then have as many zones as you want, such as hot water / upstairs / downstairs. That can be extended to any number of zones, unlike the mid position valve which is really only usable for 2 items, as it was designed specifically for installations with a hot water cylinder and only a single heating zone. Using it for anything else will have a variety of problems, one of which is that most room thermostats don't have changeover contacts.

[@johnmarshall2660]

@@jwflame Thanks for reply wasnt sure after 5 years you would see it .... Okay I had this valve for a while and installed last weekend and piped up but left the valve in the locked position so both ports open till I get my head round the wiring ... the 2 room thermostats that my daughter has are Danfoss TP5000 WiFi for Upstairs so only 2 connections (???) and a wired TP5000 which has Common ... NClosed and Nopen for downstairs, so thats okay in place of Cylinder Thermostat position ... there is no Cylinder Tank as its Direct Hot water from Boiler ... the Programmer is a Potterton so going have to check connections from that as I may have only wired one set of contacts to boiler when originally installed . looking at your wiring I think it will work but maybe trial and error ..

[@leifhorup111]

Excellent explanation, I am using the S plan system on my new Grant external blue flame condensing boiler because I didn't understand the Y plan System which according to Grant requires a RB1 relay which I didn't understand,

[@shauneboy1967]

as ever, great video... but this one comes with a big thank you as well as I have this setup at home and always wondered how it switched between CH & HW just using 1 valve - looking forward to the "inside the 3 port valve" video

[@Mr_CB]

Thank you for a very helpful and informative video.

[@sylvestrelechat8466]

Thanks for the reply John. Nothing has changed since the Ch was turned off in March so I suspect it may be the boiler stat or overun stat playing up. Many thanks, G.

[@barnzla]

Hi JW, great video, thank you. If I want to remove the room thermostat and add a wireless thermostat such as a Hive system, I would replace the programmer with the hive receiver unit but then I am correct in thinking I would need to connect 4 and 5 in the wiring centre after disconnecting the thermostat?

[@jwflame]

Yes - see this video: kzbin.info/www/bejne/qne3YnSAqMeAnNE

[@barnzla]

John Ward superb just the video I’ve been looking for, thank you

[@tonyfot0]

Thanks for clear explanation of the various circuits. Past issues resolved and completely rewired my 8 bar connector from the previous installers poor wiring technique.

[@PedantsRevolt]

Very helpful video. One quick question... If the programmer goes phut, is there a trick one can use to get hot water? ...For example, turning the system off at the fused spur, connecting the line terminal to "DHW on", then turning the system back on?

[@jwflame]

Yes - exactly that. Remove programmer, add link between L and HW On. Same can be done for the heating if required.

[@PedantsRevolt]

@@jwflame Ah, great: that's good to know. Thank you, John --- much appreciated.

[@billpoupart4724]

Hi John, As ever great detail and explanation. Would you be interested in making a video on how to install a Nest Heat Link control with a Y plan system. All other information i have viewed does not go into the level of detail that you do.

[@kevincuthbert3058]

Sounds like you don’t have a HW off connection.

[@vladimirstafasani4630]

This is an excellent video thank you John much appreciated

[@roberthuntley1090]

Thanks for excellent series of videos re central heating. I'd like to pick your brains if possible about a possible change to my Y Plan wiring. I'm having a new boiler installed next week, and unlike my old one it it should have a overrun wiring connection between the boiler & the pump. Unfortunately, the boiler and pump/wiring centre are a long way apart which means that running a new cable would be difficult/disruptive. I've come up with a 'cunning plan', but would welcome some advice re its compliance with wiring regs. etc. Presumably this is a frequent problem when old boilers are swapped out. At the moment my system runs a neutral feed (black core from a TC+E cable) all the way from the switch-fuse unit in the kitchen to the wiring centre in the airing cupboard, and then returns a neutral feed back to the kitchen using a different core (blue core from a pair of 3C+E cables) to the programmer (which is inches away from that switch fuse unit). Running a direct neutral from the switch-fuse unit to the programmer would release that blue core and allow it to be repurposed for the pump. NB - The other blue core in that pair of 3C+E cables is already used for a switched live (turns on boiler) so I assume that practice is OK (was installed approx. 30 years ago). Not so sure about the direct connection between the switch and the programmer though. Many thanks in advance.

[@87smurf]

Hi John, my house has an open fire with a back boiler still in use, I'm wanting to install a pipe stat which will send power to the pump when the temp is up, I'm having difficulty understanding what way to wire the statz would you have any knowledge on this? Thanks

[@clivepritchard]

I'm trying to use a 5 wire motorized head to replace a 3 wire installation. Can this be done and if so what do i do with the extra 2 wires? Any advise greatly appreciated.

[@TCSC47]

Thanks John. Very helpful.

[@zuddy6]

Hi John ,I have an old V4073A valve it has a relay plugged in on the side one of the pins has snapped so was wandering if you know where I can get hold of one of these. Thanks

[@PlanetThisThatandEverything]

HI John, quick question, If wiring a s plan but instead of a separated programmer and room stat, you had a programmable room stat, would it wire up in the same way but the wires going to the separate programer and room stat, they would go to the one place at the programmable room stat? hope you can help

[@jwflame]

Yes, all you need is the thermostat contacts between L and the heating valve brown wire (terminal 5 in the video). If it's an existing system, the existing thermostat wiring can be used, but either set the existing programmer to On permanently, or put a wire link in place instead of the programmer. You will still need the other channel of the programmer for hot water. For Hive / Nest / Tado type systems, the receiver unit replaces the programmer, the old thermostat is disconnected and a link installed instead (between 4 and 5 in the video). The receiver unit controls both hot water and heating, with the new wall thermostat , phone or tablet connected by wifi / radio signals.

[@_tomasz]

Hi John, great video. I have a bit of OCD and the fact that there is a scenario where the motor stays continuously powered on gives me sleepless nights. I was thinking about improving the design. What if I will add NO Relay on Grey wire which will be activated by voltage on White wire? That should reset the valve to HW position every time there is no demand to CH? Whats your thoughts on that?

[@davidjenkins9842]

Outstanding! Do you also do a similar vidoe for multi-zone UFH by chance?

[@haribo1468]

I have recently installed a hive thermostat for hot water and heating on my Y plan. I have realised that is gives priority to hot water, is there a way of altering the wiring so that when I ask for heating, the hot water doesn’t get heated at the same time? Thanks

[@jwflame]

The connection for HW Off is probably missing or not connected correctly.

[@kraddis6759]

can I ask a pedantic question. what is the purpose of the grey wire on the 3 port valve. If it doesn't do anything in term of switching the valve or move it's position then is it required? Does it need it to stay in the default HW position?

[@jwflame]

Grey is used to select heating only, and can also be thought of as 'hot water not required'. Without it you would only be able to have hot water / hot water & heating.

[@jakes5873]

Hi John, wonder if you can assist me. I'm wiring a Y plan via a smart wiring centre, but in the wiring centre I've only got 2 terminals for the CYL stat. The CYL stat itself has obviously got 3 wires (C, 1 and 2). Just wondering if you knew which 2 wires should be used?

[@kraddis6759]

thanks for taking the time to make these

[@darrenmillar6911]

Hello. Can you help me figure out how the Hive Controller would fit into this to replace the programmer. Also does the power supply have to feed thru the controller

[@andybrown8290]

Hi John, I have a what I believe is a vented Y plan system, which I think is fully pumped. It was installed 29 years ago. The programmer has been changed to a digital one some time ago. Industry standard back plate so nothing changed in the wiring. Recently I replaced the pump and 2 way valve which were faulty, I have noticed when doing this that the water didn't seem to turn off when the water was hot via the tank thermostat. On inspection of the tank stat, it appears it may not be working, but I also think its never been wired correctly, as it only has C and 1 wired, so no wire to 2. I'm thinking (In HW and HC Mode) this would cause the heating to also turn off when the water tank stat has a signal to satisfy the waters hot (If it was working). I plan to replace the stat and add the wire required. Any thoughts would be appreciated, also advice on checking the stat is not working. I believe it may stuck, permanently connecting C and 1. Thanks again for the fabulous tutorial presentations. (the original installation was done by tradesmen) Kind regards Andy

[@jwflame]

On Y plan, the cylinder thermostat must have all 3 terminals connected, as the HW OFF signal is required. If that's been wired incorrectly, check all of the other wiring as well, as there may be other problems.

[@andybrown8290]

@@jwflame I did a diagram some years ago of the wiring and it's still as it was back then. Which is all correct as your diagrams in your post, except it only ever had two wires to the C and 1 nothing to 2. The tank stat doesn't switch off the pump and boiler when its hot. Tried turning it right down. I think it needs replacing and the missing link to the hot water stat (2) installed.

[@golemsnatch5755]

Hi John. Can you tell me if it is normal for the valve to remain in the CH position if that is the last position it was in when the programmer switches off both HW and CH at the end of the timed period.

[@jwflame]

Yes, it's because with everything off, the grey wire is energised (HW off), which holds the valve in the previous position.

[@golemsnatch5755]

Wow that was quick. Thank you very much that's put my mind at rest.

[@hubcap2k]

It is madness that the valve motor stays energised, hot and buzzing when nothing is switched on. Ideally when no heat is required the wire should not be energised.

[@abdurrehman-zs4qe]

Very well explained much appreciated

[@0o7spy]

Hi John. Great video. Just moved into my house and found that when I turn the mains on the boiler the pump comes on straight way regardless where the thermostat set on or even when it’s turned off. Any ideas?

[@nadiaa4231]

Hi John, thanks for these great detail and explanation. I also have Y Plan setup in my house the isssue is that my CH doesn't work alone ...for CH to work I need to open HW also. when you ON CH only boiler switch ON and then goes off after few seconds, I thought it;s may be due to wiring issue and after looking your tutorial on Y plan I found that I don't have any wire going from programmer HW= OFF to 7 on the Junction box ? does this wire really needed in Y plan setup? thanks

[@jwflame]

HW OFF is required, it will not work properly without it .

[@nadiaa4231]

Unfortuatly controller timer is downstair and junttion box is upstair near the water tank so not possible to run the separate cable...any other idea you can think please?

[@golemsnatch5755]

Hi John, have you any idea why the pump on this system would suddenly decide to keep running even when the thermostats are satisfied and the boiler shuts down. It has only just started doing this and turning down the room or boiler stats has no effect neither does turning the controller off (not isolating it). Valve was changed for a new one 8 months ago.

[@jwflame]

Most boilers have an overrun function which keeps the pump running for a while to remove any excess heat from the boiler, and the pump is controlled via the boiler. If it runs all the time even when the boiler does not, then the fault is in the boiler. If both the boiler and pump operate when the thermostats/programmer are set to off, then the fault is probably with the zone valve sticking open .

[@Chris.P.Noodle]

Hi John. We recently had a new boiler fitted on our old y plan system that only has the option for water only or combined water and heating. Will this affect how the new 3 port valves with the built in switches work? Cheers.

[@paulrossiter9567]

Excellent explanation yet again 👏👏👏

[@greatplumbersuk3577]

JW is a Don. Great stuff sir

[@iandavies7168]

Hi John. Top video, thanks. one Q. please: on the Honeywell instructions you show (I have one to retro-fit after a Siemens has failed), it says: "A Class ‘A’ switch (having contact separation of at least 3mm in all poles) must be incorporated in the fixed wiring as a means of disconnecting the supply. The system must be appropriately fused." So that is the feed with a 3A fuse at the main junction box, yes? And not a separate switch much higher up (next to) the three port valve itself? My plumbers's advice was to avoid wiring the new one into the existing terminal strip (for fear of getting them back in the wrong places) and instead, to wire the new port valve into a five way connector block with the existing 5 wire lead coming out of the junction box / connector block 'intact'. (& If i do that, what Amp terminals do in need for connectors please?) If i Do need a switch (as well as the one on the main fuse box) then surely this is where to place it? Pretty sure I don't but if I do, i'll be back to ask how to wire one : )

[@jwflame]

Yes, that's just the 3A FCU for the whole system. They all have the 3mm gap etc. You do not need any other switches. Connectors can be anything of 3A or above, although larger ones such as 5A or even 15A are useful if multiple wires need to be put into each terminal. Most wiring centres have 15A terminals.

[@iandavies7168]

Thanks John. You are a star. Does that (putting a connector block in line between the two x5 core cables and in a junction box rather than rewiring into the exiting strip) sound like a good idea? Or is it overkill in itself and the thoughts of an easy-life plumber and not actually 'what you should do'?

[@jwflame]

No, it's just a waste of time. Will take far longer than just wiring into the existing terminals as there would be both a plug and socket to wire. Won't be of any help if it needs to be replaced in the future either, as it will still involve removing the existing wires and connecting the new ones. Just remove the existing and connect the new to the same place. Make a note (or photo) of where the wires are connected before removing anything.

[@tombelmonte2502]

Thank you Mr Ward nice video presentation GODBLESS!

[@jtk1ify]

Thank you for presenting these informational videos John, you have helped me have a much better understanding of such systems i have a problem with a y-plan system in my new house, i think that it may be related to the grey wire being live even when the programmer both HW and CH are both switched off, which if i understand correctly in turn raise the orange wire to approx 100v potential. The boiler will not switch off unless the the switch wire is physically disconnected , and then it stays off when the switched wire is reconnected. however the problem reoccurs when hw and ch are switched on then off could you give me some guidance thanks JTK

[@jwflame]

Some modern boilers do have the problem that 100V is enough to activate the boiler, and hence the system stays on when not required. This can be fixed by adding a device such as this Worcester one: www.dhsspares.co.uk/product/worcester-87161092750-rc-device-1015509 between the orange wire and neutral. The item is just a capacitor and resistor usually sold as a contact suppressor, so this: cpc.farnell.com/ampohm-wound-products/fe-sp-hdr23-100-100/contact-suppressor-0-1uf-100r/dp/FT00715 type of thing should fix the problem for a lot less.

[@davidbreingan4173]

Hi JohnThanks for making these videos, very informative. I have a question I hope you can answer for me. I have a Y plan heating system but the programmer has broken down (I think its the circuit board) and it is on a standard backplate but its an old Landis & Gyr programmer and can't find a replacement anywhere. I have however got a redundant programmer at a family members house with a standard back plate but their system is an S plan system. Can I use their programmer on my backplate even though one is an S plan and one is a Y plan? The Live, Neutral HW on/off and CH on/off are in the same numbered ports so they match ok.Many thanks Dave

[@jwflame]

It will work - the rest of the system is mostly irrelevant. Y uses more wires than S, but all programmers have all of the connections for all systems.

[@davidbreingan4173]

@@jwflame thank you. Much appreciated.

[@AlanAnsell]

hi john can you help out i have the system above but the only way to get central heating on is to turn the cylinder thermostat up to 80 any advice welcome

[@AlanAnsell]

its ok sorted it cylinder thermostat 2 not connected to 3 port 7

[@chrisbartrum3201]

Hi John, a great series on CH. I still have a bit of confusion @ approx 4:00 to 4:10 when the pump is connected to the PL line for the boiler. Does this connection take place in the control box. I have a worcester greenstar camray utility 18/25 wired up as (ww2.justanswer.com/uploads/PL/PlumbersMate/2012-10-26_182739_y_plan.jpg) Hope you don't mind me asking. Thanks for the excellent video.

[@bulthy1958]

Brilliant,just the info I needed.

[@davidmoore8032]

Just Brilliant. What a great explanation. Thanks very much.

[@stephenanderson2079]

Hi JW. You certainly know your stuff and expertly delivered. I have accidentally pulled out some of the wiring in the strip terminal that connects the 3 port valve, pump, controller, boiler & `stat. (a shelf collapsed pulling wiring out....eeek) The Honeywell 3 port valve (40003916-001) has 6 wires attached, all info online I can find have 5 wires. I have identified and can connect the wiring for each other component, but my system does not have a room thermostat. My problem is....How to wire the 6 tails from the 3 port valve. One colour I cant identify, `cos i`m colourblind and where to connect the white wire that would normally connect to the room `stat. I hope this is clear and many thanks in advance if you could assist

[@kpereira8910]

Thank you Sir. Brilliant video as always. quick question though, If Boiler doesn't fire up on "CH only" mode but valve moves to "H" and has 240V on the orange what could be the fault? also boiler fires up on both "HW only" and "HW + CH" modes, and everythinh works fine but "CH only" boiler doesn't fire up and no heating. Any advice will be highly appreciated. Sorry i'm new to the trade. Thank you.

[@jwflame]

If you have 240V on orange and the boiler isn't working, orange isn't connected to the boiler.

[@tommyatkins6205]

We have an older oil boiler with no SL so would I wire the boiler live to port 7 ?

[@jwflame]

No, boiler L connects to 8. The pump L will need to connect to 8 as well. No connection to 1.

[@taddy666]

Hi JW. Superb videos - thank you so much for this and the explanation of the internal circuit/mechanism for a 3 port valve.I'm trying to diagnose a problem with my system at the moment and have noted that when the programmer is set to HW only I'm getting a 240V reading on the 3-port valve's white wire when the cylinder thermostat is calling for heat. Surely this is incorrect!? The white wire is connected only to the programmer so should be off when set to HW only. Could the 2nd switch inside the 3-port valve be stuck so that the white is getting 240v from the orange? The water is heating but the radiators are also on. Thanks in anticipation. Tom

[@jwflame]

The switch could be stuck on, the other possibility is that the programmer has failed and is connecting power to white permanently. A test with the white wire disconnected from everything apart from the valve will confirm which.

[@taddy666]

Thanks JW! Will try it later.

[@johncooney4004]

Hi John. Great video, as are all you other ones too. I've got an old Y Plan system that has an additional room thermostat called a Watchdog. This will turn CH on when the temperature gets to a certain level regardless of the programmer setting. The theory was that it's more expensive to raise the temperature in a completely cold house than a house that has been maintained at a certain minimum level of warmth. How does such a thermostat wire into the Y Plan arrangement? JC

[@jwflame]

The thermostat contacts connect to permanent line and the white wire of the valve, 1 and 5 in the video diagrams. When the temperature falls below the set level, the thermostat connects power to the white wire, which will override the programmer and normal room thermostat.

[@surendrasinghdhanjal5835]

Excellent video

[@jjjohniee]

My friend thanks you very much, facing a cold Boxing night I went and changed her "dead motorised valve" by wiring in a different head without taking the old one off the valve, just locked it into mid position until I can get round to replacing it with the correct head. I also turned the cylinder thermostat right down so hopefully it won't cost her a fortune?!?!

[@jwflame]

Not ideal but it will get the heating on. A lot of the valves can have the head removed without draining the system, in which case you can just swap the new one for the old.

[@jjjohniee]

Hi, Thanx, no@@jwflame, she moaned about the shower being too hot! lol, today went and changed her sequential mixer (which had also gone west) for 2 speedfit shut off cocks which owing to the fact she has extremely low pressure actually works a lot better than when the sequential was working properly, again not perfect but I think it actually looks nice too?!? Also changed a jammed TRV for a normal without draining at all, just popped it off, finger in, new one fully open, popped it on. Was extremely surprised how little mess! Think I might have to give up driving instructing. Hope you had a "Happy Christmas!" :-)

[@robertambrose2082]

What do you do if the boiler is an old back boiler that does not have a switch live, only a permanent live ?