Combi Boiler with Two Heating Zones, 230V Switching
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- Опубликовано: 4 июн 2024
- Wiring for a combination boiler with two central heating zones, each zone controlled by its own thermostat.
This is for 230V switched boilers only - NOT appropriate for boilers with 24V or other non-mains inputs. Part 2 covers those: • Combi Boiler 2 Heating...
Can be used with almost any thermostats, including Hive, Nest and other smart devices. Also applies to wireless, wired, mains powered and battery thermostats.
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Probably the best explanation of wiring zones valves I have heard
I was really impressed too. The marker drawing/diagram was basic but very effective
you should sell t shirts with " JW taught me my job " on them.
A fantastic yet simple explanation of multiple heating zones.
Many thanks John from all learning this.
I'm a sparks and I know this stuff inside out and I'm still watching these vids says a lot for the channel.
JW - is by far the most concise teacher. ( Thank You John W. For this Great Video )
Thank you for a most thorough but concise and informative explanation JW.
Clear, concise and straight forward explanation. Best one on YT. 👍🏼
Amazing. I’m a sparky and still benefited greatly from your explanations and delivery. Thanks.
Thank you John
For explaining how to zone on 230 volts.
This helped me understand what was going on in the wiring centre, disconnect my old stat (at both ends) and add in a hive receiver next to the centre - great video, thanks
John, you're explanations are superb. Really first class stuff. The paxman like delivery is a bonus too :-) . Thanks.
Brilliant tuition and video John, very well presented and animated, best on the internet, helped me instantly, thank you!
Thanks for this video, it completely helped me wire 2 zones to a combi!
The best video going when it comes to understanding the wiring of a 2-port valve. Who would have thought brown doesn't go to brown!?!! Thank you :)
Amazing. Great clear and thorough video. Thank you
This could be sold as a training video!!! Thanks JW!
Brilliant very professional and well set out. Best one on RUclips keep it up 👍👍
John ward - Aka - JW - is by far the most concise teacher and greatest electrician on the net.
Anytime im stuck - JW - pulls me from the muddy waters.
Thanks JW 1UP
most easiest to understand explanation of wiring controls ever
Well explained. Thank you John, you're could be a good training teacher!
I love your vids. Trying to be a sparky for many years even tho passed out NVQ 1-2-3 2010. Could not get proof of work done as lack of interest from sparks if your over 19 slave labour rate.
Sorry for rant. Anyway your vids are so good and helpful for some one who has little time on the tools but still interested in staying relevent.
You really are a valuable source thank you.
Excellent as always! Thank-you.
Just what I was after - great vid
Brilliant John.
Great video. Thanks
Excellent video. Just what I needed.
I really enjoy your work, BR
Am a plumber but just couldn’t find a good diagram for adding underfloor heating to Combi with two zone valves and modern 230v programmable thermostats.... thank you, after five mins watching, my brain clicked into gear... the wiring diagrams I had still don’t make sense but it’s all working now thanks to you...
Hi Andy,
I am looking for the same thing connecting underfloor heating to combi but not sure how to do it. I would very appreciate it if you could let me know how you did it. Many thanks
Thank you very much, you’re the best !!! Very good explanation and made a lot of sense.
Fantastic explanation JW thank you so much.
Hi John. Great video. Any advice for the best smart heating system which I could retrospectively add to my boiler (opentherm compatable) and underfloor heating (7 zones). As I have basic stats today it's working as a simple 'On(100%)/Off' system which means i often overshoot my desired temp and my floor is often too hot. I think I need to find stats which enable modulation (individually for all zones) but I'm struggling to find the right manufacturer. Thanks!
Excellent video, well explained!
John, you are the best 👏🏼👏🏼👏🏼👍🏼
Excellent explanation.
Very clear and professional video. I have a couple of questions pls. 1) which brand wiring centre would you recommend for Hive, and 2) I am trying to understand how the bypass will be installed (or what it looks like pls in a setup). Thank you ever so much
This is really good. Thank you.
Very clear explanation / description. No programmer is shown in this. Not often mentioned in various explanations available (which often show a HW. cyl stat); is that most /all combi systems have no HW cylinder or stat & the boiler supplies HW on demand. I assume a combi's HW output is triggered by an internal flow valve; you turn tap, water flows, flow switch operates, boiler fires. All that is needed are the zone stats to fire the CH as shown in your video plus a timer/programmer to automate CH. The HW side of the programmer is unnecessary in this set up.
Excellent explanation. Thank you.
Spot on explanation really helpful
brilliant explanation. thank you.
Brilliant explanation 👏
Thanks for explaining this so clearly John. I'm fitting 2 Hive single-channel thermostats and I thought I was going to have to wire the receivers into the circuit through a new spur or something.. I'm pleased to see it's easier than that! I have a few questions (excuse my ignorance!)
1. On your diagram of the wiring to thermostat / receiver it shows the same connection from L on the boiler going to L and 1 on the receiver. The Hive wiring diagram labels L as Permanent Live and 1 as Common. I just want to check that I need to use a short piece of wire to bridge between L and 1 on the receiver?
2. What specification ofcable should I use for this?
3. I see some of the connections on the wiring centre have as many as 3 wires going into them. Do they all fit in the hole or will I need a connection block to connect the 3 wires into the hole?
Great video. I'm wiring ideal vogue what changes would I need to make for the set up to work?
Thank you for lovely explanation really helpful video
Excellent explanation, I have never worked with a boiler or any electrical wiring other than dashcams and the odd splice into a car live wire for some 12v power.
After watching your video, I was able to setup zone 1 of my Hive Dual Zone heating to replace my current thermostats, took me around 40mins including stripping/trimming cables, now I just need to cable tidy and then do the second one!
Really appreciate this video and diagrams, very informative and right to the point.
Hive wanted £175 for this install, all I need is a little trunking but the rest is neat so i'm happy! :) - Anyone reading this comment thinking of having a go, just make sure you invest in an electrical tester to make sure the switch is isolating the circuit correctly as explained in this video, better safe than barbecued!
Great video, very clear. The issue I have at a client's property is that the wiring centre is at the opposite end of the house from the boiler and where the new Hive reciever would be. Currently there is only a 3 core and earth from the boiler/reciever area to the wiring centre which leaves me 1 core short. Would it be possible to supply the L,N and E to the pumps locally at the wiring centre ( fused down ) and use 2 of the cores in the existing 3 core and earth plus the earth as the switch cores? this would mean that there would be 2 circuits at the wiring centre. I would clearly label this at both ends but Im just wondering if it is ok or a total no no? Thanks in advance.
You are a great teacher 🎉🎉🎉
Had to wire a combi to a cylinder as well as central heating through 2 x2 ports 10 years ago, what a head scratcher that was, had to run it through a relay switch if I remember correctly.
Should basically just be the same only with three zones instead of 2. Unless you want hot water priority, (ie if hot water is demanded then heating is off). In that case you’d do something fancy with the NO and NC contacts of the hot water thermostat contact. Specifically, the power that goes to the heating side of the system should be on the NC side of the hot water thermostat, so the whole heating side turns off when the water is demanded.
Excellent information
Thank you John. I'm not an electrician but have benefitted from so many of your videos. I have a problem relating to the above. We have fitted a Heatmiser UH4 control unit with wired 230v Neostat V2 thermostat/timers. The Heatmiser gives the option to run underfloor heating zones along with a radiator circuit. I wondered if you have any knowledge of those products? The electrician is scratching his head because our Worcester Bosch Greenstar boiler asks for a 230v supply to its switching, the Heatmiser wiring diagram seems to show a volt free connection coming from the control unit. As a result, the boiler doesn't switch off at any time. Sorry if all of that is confusing.
Thankyou very much very well explained
It'd be better with ONE 3-port valve instead of 2 two-port valves.
Hi JW, On pin 9 when both stats call for heat, why doesn't the voltage from both valves either add to create 440v assuming they are in phase or cancel to 0v if there's a 180deg phase shift introduced, with the first point being most likely.
Will this work with valiant ecotec plus 832 Combi boiler? It has connections ‘RT’ next to ‘LNPE’ inside this boiler. The RT connection has 2 terminals though? This is a 2 zone system with the Drayton 230v ZA5 2-port valve. I am also installing 2 thermostats, they are the danfoss TP5001M 230v with V/F output. I am right in saying the switch line to the thermostat will connect to normally open contact? Great video by the way, any advice would be appreciated!
Thank you mr ward
Thanks Dude. Love your vids.
Thx so much…i was searching for this…
Will the central heating thermostat be able to switch an external heating pump on directly aswell as the boiler. I have a combi boiler and I think the internal heating pump is not powerful enough to pump water around the house. I want to put an external pump in the system but need it to be controlled so it turns on and off and not powered all the time. Looking at the circuit diagram on your video, instead of having zone valves can the thermostat control the external pump the same I.e when thermostat is turned to required temperature the pump starts.
Thanks
Could you connect the grey and brown wires together at the 2 port valves, and then ditch the perm live to the valve? You would still have the ability to switch on the boiler with the postition switch within the valve, however it would be fed from the programmer not the main live. You would then only need 3Core + Earth cable
Currently considering switching to tado smart heating. Have ESI wiring centre plug and play in at the moment (new build). Need to swap to a more analog wiring centre. 2 zones. Combi. Will this work?
Great video, one question if one zone is an underfloor zone with an additional pump would you take the sw live from the zone valve?
UFH pump is connected to the thermostat for that zone, so it only runs when that zone requires heat. Thermostat 3 in the diagram, which is also the brown wire for the valve.
Nice explanation
Another excellent video...
JW, cheers your videos are fantastic. I have a question if I may. My boiler doesn't appear to have a switched live. I currently has a link in place labeled ROOM STAT/TIMER. My boiler is constantly firing up even though the thermostats are off. Have you seen this before?
That link is supplied with the boiler, so it can be powered up immediately after installation without having to connect external timers or thermostats, mainly so that the gas side of things can be set up properly. Normally that link is removed, and it's those same terminals where the room thermostat or other controls are connected.
However some boilers have multiple options for connecting external thermostats, so you will need to check the installation instructions for your particular boiler.
Just find this video very good explanation. I wish someone make video about 2 zone heating with 2 pump or more with Relay to stop backfeed one for other. Always confuse me that systems 😂
Nice vid thanks ..might be worth mentioning that if using a Honeywell wiring centre and going on their wiring diagrams the bridging in center may cause confusion for future fault finding if engineers are following Honeywell guides.
Not a criticism just an observation.
Great , clear info . Would like your thoughts on the best way you would use to balance the returns if say downstairs is bigger than upstairs . Thanks for taking for a great presentation.
Nice job thanks
If I wanted to move a radiator from one heat zone to the other and the radiators share a wall with pipes inside. Can I just daisy chain or will I need the floors up...
Understood up to the part of connecting first three wires brown blue earth. After that is become complicated. Also which wires to use 1.5mm2 ???
Dose the same principle apply if your second zone is underfloor heating?
Having an issue with our central heating system. I have a brand new thermostat, and dual zone heating. The heat pumps both work as I can wire them each to the upstairs thermostat which works but I cannot get the downstairs thermostat to call for heat even though it ‘clicks’ when turned up.
Any ideas what this could be?
Mate you a legend
Based on this can you add Unvented cylinder instead ?
Fantastic video, thank you. Would it be possible to use a 3 port valve instead of two 2 ports?
Not without extra components and thermostats which had both on and off connections.
3 port valves were designed decades ago for one type of installation - a hot water cylinder and a single heating zone.
They are of little or no use for anything else.
Hi John, just what I was after, Great, Thank you. Same principle as your diagram etc but one circuit will be radiators, the other will be for UFH in a single zone. I'm just a bit confused as to where the return pipe would fit into this as 2 separate circuits? Would I need a third 2 port valve for the UFH return and just two 2 port valves on the flow side, one for UFH and one for Rads as per your diagram? Kind regards, Paul
The return pipes just join together, no valves required.
@@jwflameTHANKYOU! I did consider that but won't UFH return interfere/mix with Rad return as that's on different circuits with diff pressures? So in a nutshell, the same as your diagram? Cheers, Paul
Brillant video , thanks . I am in a process of connecting an UFH ( zone 1) and radiator system (zone 2) I am using 2 2port valves as the UFH is only 1 large room , 2 hive thermostats , I am struggling to understand where to wire the UFH pump . any videos of yours available on that subject ?
For a single UFH zone, the pump is wired to the thermostat switched output, so it runs at the same time that the valve is open. Terminal 7 or 8 in the diagrams in the video.
@@jwflame many thanks it makes perfect sense
hi John. thanks a lot, helpful stuff. The plumber has attached an extra Wilo Para pump to the zone 1 side (to help with underfloor heating). Would I attach the live (of the pump) to number 9 in the wiring centre? (the pump only has L,N and E) That way, it would come on when called for by thermostat receiver 1? or is the incorrect? anyway else could help too? thanks
No, if connected to 9, that pump will run when the boiler is on regardless of which thermostat is used. If it's for zone 1 only, connect it to 7, which is the switched output of that thermostat only. Numbers refer to the diagram in the video, your installation may have a different arrangement.
The UFH pump should be part of a manifold with a mixing valve, so it only pumps water for the UFH, and nothing else.
@@jwflame thanks a lot 👌🏻
John! How might this work if i then introduce a 3 way zone valve for hot water in if we were using a system setup?...
It doesn't. No one should be installing new Y plan / 3 port valves, they are only suitable for a system with hot water and a single heating zone, nothing else.
To add more zones or a hot hot water cylinder, it's another thermostat and a 2 port valve.
Other videos covering those: ruclips.net/p/PLVsHvs2Suqmr5HtxgbInR4bXmH0kLseWc
Thank you Mr John for clarifing and simplifying. I have a question. Do we need a programmer? Just thermostat enough? And what about hot water how it is controlled for each zone? Many thanks
The arrangement in this video would be used with modern programmable thermostats, which have both time and temperature settings. it would be possible to use a separate programmer/timer and thermostat but there is no point - it would cost more, be more complex to install and provide worse control of the heating.
There is no control of hot water here - combination boilers heat the hot water on demand.
Other videos in this series cover hot water controls, ruclips.net/p/PLVsHvs2Suqmr5HtxgbInR4bXmH0kLseWc
@@jwflame thank very much Mr John
Hi , I have this system , I have 2 ESI programmable room stats . I would like to put open therm connected to my system , any idea what would be involved to do this , thanks
That’s a great video thank you. Would it be the same for underfloor heating zone valve instead of two central heating zone valves? If so how would I connect the pump wiring?
Many thanks
The valve is the same. If it's just a single zone, the pump is wired to the switched output of the thermostat, the same terminal as the brown wire to the valve.
For systems with multiple UFH zones, a separate UFH controller would be used, which will have connections for the pump, actuators and thermostats.
@@jwflame thanks very much John much appreciated
Diagrams and instructions are very precious and clear I wonder if there are any possibilities of wiring zone valve and 3 port motorised valve in a single wiring centre. While I was on unvented course the instructor told me we could wire two different valves but I like to know how. It will be very grateful if you could made such video please?
Thank you JW
www.flameport.com/electric/central_heating/heating_wiring_Y_plan_unventedHW.cs4
@@jwflame cannot thank you enough for that Sir.
It'd be better with ONE 3-port valve instead of 2 two-port valves. Quite possibly in upstairs downstairs case, heating on both likely not necessary. If they are both needing heat, another switch is required to allow the 3-port valve to return to its mid position.
John. Could you please explain what a dry contact is please? Thanks in advance
Switch contact that doesn't have any voltage connected to it.
Like the thermostat contacts in this video before the link between L and 1 was installed.
Also called 'volt free'.
Great vlog as usual but where is your time control as required by current regulations
Very informative Thank you.
just what i am about to do, one for the kitchen and bathroom and one for the rest, only need the kitcen and bathroom most of the time as wood burner does the rest.
It'd be better with ONE 3-port valve instead of 2 two-port valves. Won't need an automatic bypass for pump overrun and means only need to wire one valve in.
Hi Quick Question , If Zone 2 was a UFH system ( pump & Actuators ) would i attach their 230v Power To point 8 ? on the diagram . So they would switch off when the Hive is turned off ? .
Would this also work if Zone 1 and 2 was on at the same time and i turned off the UFH/Zone2 ( would the Pump and UFH turn off ) ( I assume they wouldnt be getting any power from the orange ? )
I have the same question.
@@robday3968 Rob , I converted my single zone to dual zone ( UFH and Radiators ) last weekend . From my UFH wiring i had a Brown & Grey wire ( Brown Sleeve ) . These both connected to point 8 on the diagram . This then meant the pump and actuators turned off with the zone . My setup was using two Hive thermostats .
Hi John, great video can you help on external 3 channel programmer to Worcester gas
Thanks
John
On a 2 zone combi system. Could both valves be removed and pipe work bridged where the valves are removed and a simply receiver and stat be added directly to the boiler for call for heat without altering any other pipework?
Yes, it would just end up as a standard combi boiler installation.
Hi John I have a Greenstar combi CDI with comfort 11 RF installed, following your diagram to the letter.
everything plumbed and wired.
Looking at the boiler wiring I find that LS is linked to LR so I am now stuck as when to put the orange wires from the 2 port valves.
The link is removed, the orange wires connect to LR.
The link is there so that the boiler will run all the time when heating is selected on the front panel, it's intended for testing purposes only when the boiler is installed.
This is a great overview. One thing that's always confused me (as a lay person), is the circuit route (thermostat -> wiring board -> boiler) carrying the actual power for the boiler itself? Or just enough power to 'activate' the boiler, which then draws running power from an independent connection?
The thermostat is just an on/off signal to the boiler. Also note that this wiring is intended for gas or oil boilers, so the electrical power used is only for the pump and controls, typically under 100 watts.
Electric boilers do exist, they would have a separate high power connection for the heating elements, with the thermostat wired as here, just for on/off control.
@@jwflame Thanks. I actually forgot it's gas combustion that's heating the water, not electricity!
@jwflame hi do you have a video on a combi boiler with ufh manifold & room stats
Will this working with wireless receivers/thermostats??
Hi great help you are!
If I had an underfloor heating pump how would I wire it in? If it’s 3 core without it being on all the time?
Thanks
E&N to the earth and neutral terminals. L to the switched output of the thermostat (3 in the diagrams, also the same as the brown valve wire), so the pump only runs when heat is required for that zone.
@@jwflame thanks mate
nice job thanks
It'd be better with ONE 3-port valve instead of 2 two-port valves.
@@millomweb stfu. Don't need same reply to every comment
Hey JW, due to building works at home I am having to use the immersion heater now to heat water for about 5 months.
Is it cheaper to leave it on permanently being controlled by its start or only use the immersion on demand.
Has anybody ever carried out a proper study on this with real figures and temperatures??
It's cheaper to switch on when hot water is required, as when the water is hot, the losses from the hot water cylinder are greater, as the temperature difference between the water and the outside environment is also greater.
The saving will be largest with an old, poorly insulated cylinder where hot water is only required for a certain time each day, so most of the time the cylinder is cold.
However with a modern well insulated cylinder the losses are small, and if large amounts of hot water are required (so the water is hot most of the time), then the difference between heating when needed and on all the time is insignificant.
Do the end switches “make” if you have no power and simply push over the lever to manually open the valve?
No. The manual lever only opens the valve partially, should only be used when filling or draining the system.
I've a buffer thermal storage tank. I need to turn on a load when top stat drops to 45c and not turn off until bottom stat reaches 50c. Can anyone tell me what device I need to do this? tia
Is it possible to have a 24v thermostat connected to the zone valve controlling the radiators and a 230v stat connected to the zone valve controlling the u/floor heating on the same combi boiler?
It’s a valliant combi.
I’m pretty sure I can but just wanted some reassurance 😁
If the 24V thermostat just uses 24V for power and has volt free contacts, then it could be used, the thermostat contacts would switch the 230V for the zone valve as in the video.
If the thermostat switched output is also 24V, then it would would require a relay with a 24V coil, the 24V thermostat would power the relay coil and the relay contacts would switch the 230V power to open the valve.
In both cases the thermostat would require a 24V supply from somewhere.
@@jwflame thanks for the reply, keep up the great work 👍🏻
Can you add the open therm wiring for one of the valves in a 2 zone system
As far as I know, opentherm would not be possible with a multi-zone system, as opentherm takes over control of the boiler (opentherm is a digital connection that goes straight to the boiler from the thermostat)
Sir, what type of cables be used in boiler electrical wiring, please. Thank you.
Heat resistant PVC flex, 0.75mm² would be the usual choice. 3,4, or 5 cores depending on what is being connected.
Hi if one zone was underfloor heating what would pump be wired to?
UFH has it's own pump, which for a small single zone would be connected to the thermostat for the UFH.
For larger installations with multiple zones, the UFH pump is connected to a dedicated controller/wiring centre for the UFH together with the thermostats and zone actuators.
How would I remove the second zone? We have a very small second zone in our bedroom and ensuite that we do not use as the thermostat makes a big CLUNK when it turens on or off and wakes me up! I'd rather have the entire house come on and off together.
Find the brown wire for the zone valve in the wiring centre and connect it to the brown wire for the other zone valve. They will then both work together from the same thermostat.