s plan central heating 3 zone valves

I can't see how you can have a system with a 2 port valve and a 3 port valve. As the 3 port can't be closed.

Whos got a 3 port valve?

Have seen a few clacker valves in the past, always seem to be ceased up though

Ok mid position valve

Wasn't having a go Will, its just that the OP reckons he has 3 2 port valves only, yet only to zones?

This is what throws me out.

feebs73 said:

Hi Chris
Please accept my appologise, i have been out of reach recently. I have read your reply with much intrest, i did look through the cylinder book but just found a normal wiring diagram nothing about this cylinder cut off valve. i always want to do my job properly so went looking on line asked the plumbers i know, but with no luck.
could you point me in the wright direction where i could find this information as i still have not found this wiring diagram.
Just out of interest has this method been in place long as i am working on two 5 bed 3 ensuites, 1 bathroom, with under floor heating on ground floor, the 1st and 2nd each have a room stat and a zone valve for each floor, but not a cylinder zone valve, is this write??
the "made plumber" should of been "mad plumber" i have fat fingers.

Thank you once again
feebs 73

- - - Updated - - -



Hi Chris
Please accept my appologise, i have been out of reach recently. I have read your reply with much intrest, i did look through the cylinder book but just found a normal wiring diagram nothing about this cylinder cut off valve. i always want to do my job properly so went looking on line asked the plumbers i know, but with no luck.
could you point me in the wright direction where i could find this information as i still have not found this wiring diagram.
Just out of interest has this method been in place long as i am working on two 5 bed 3 ensuites, 1 bathroom, with under floor heating on ground floor, the 1st and 2nd each have a room stat and a zone valve for each floor, but not a cylinder zone valve, is this write??
the "made plumber" should of been "mad plumber" i have fat fingers.

Thank you once again
feebs 73

Click to expand...

"Hello again feebs 73",


From your description and taking it that the Heating and Hot Water system has an UNVENTED `INDIRECT` [Heated by a Flow and Return from Heating System] Hot Water Cylinder installed:

There should be `Zones` for the Heating System which from your description should be:


1. First Floor Heating circuit / zone - Zone Valve and Room Thermostat - Ideally a Programmable Room Thermostat* - regarding both Timed / Temperature Control of that Zone.

2. Second Floor Heating circuit / zone - Zone Valve and Room Thermostat - Ideally a Programmable Room Thermostat* - regarding both Timed / Temperature Control of that Zone.

* Programmable Room Thermostats may NOT be suitable for some Householders regarding their Time and Temperature setting requirements - and some people find understanding the setting requirements too complicated *

3. UNVENTED Hot Water Cylinder [Zone] - Zone Valve - usually SUPPLIED BY Cylinder Manufacturer and MUST be wired as the Unvented Cylinder Installation Instructions state - This should include wiring for the `Thermal Cut Out` / High Limit Thermostat on the Unvented Cylinder.

4. Underfloor Heating - Zone Valve - Room Thermostat [Programmable* ? or plus Timeswitch] - Pump - Manifold - Thermostatic Mixing Valve etc.

I have identified these Zones with the Underfloor Heating as No.4 because it may be wired seperately from the S Plan Plus wiring - ?


The MUCH more knowledgeable Members will be able to verify whether I am correct in this regarding the Electrical wiring / operation for the Thermal Cut Out / High Limit Thermostat on the Unvented Cylinder:

I believe that the Unvented Cylinder TWO PORT VALVE [Zone Valve] is wired to the Heating & Hot Water Controls as in the Honeywell `S Plan` BUT ALSO there is wiring from the Unvented Hot Water Cylinder `Thermal Cut Out` / High Limit Thermostat which will `Interrupt the Power Supply` to that Zone Valve in the event of the High Limit Thermostat reaching Temperature - STOPPING the Heat / Flow to the Unvented Cylinder Coil.



I misworded My explanation in My first message to You when I wrote about the Cylinder Zone `Safety` Valve wiring being `nothing to do with the Heating Controls wiring`:

I meant that the wiring for the Unvented Cylinder `Thermal Cut Out` / High Limit Thermostat was seperate / additional to the Heating Controls wiring.

That additional wiring from the Thermal Cut Out / High Limit Thermostat controls the CLOSING of the Cylinder Zone Valve by interupting the Power in the event that it operates at a High Temperature - it then OVER-RIDES the Heating System Controls.


Please make sure that You get the EXACT Wiring Instructions before proceeding with this Unvented Hot Water Cylinder wiring - regarding the Dangers that I detailed in My previous message to You.

I do NOT have the Electrical Knowledge / Expertise to advise You any further regarding Wiring up the Controls to this Heating System / UNVENTED HOT WATER CYLINDER - because of the additional wiring for the Underfloor Heating Controls etc.

Hopefully now that I have attached the example wiring diagram for the Heatrae Sadia Megaflow Unvented Hot Water Cylinder one of our Electrical Expert Members will be able to advise You on the additional Zones - converting the Diagram to an `S Plan PLUS` with the additional wiring to the Underfloor Heating Controls.


I am attaching an example of a wiring diagram for a Heatrae Sadia Megaflow Unvented Hot Water Indirect Cylinder here and I am including a link to the webpage which has athe wiring Diagram - wired to an `S Plan` Heating System / Controls system.

PLEASE READ THE DETAILS ABOUT THIS WIRING DIAGRAM ON THE WEBPAGE IN CONJUNCTION WITH THE DIAGRAM.

This would have to be adapted to an `S Plan PLUS` wiring plan AND whatever is required for wiring the Underfloor Heating Controls [?] - that Zone is probably going to be completely seperate from the `S Plan Plus` wiring[?].

The wiring for the `Main` Heating System Pump may have to be altered from the S Plan if the Boiler has a Pump Over-run - because the Pump would then have to be wired to the Boiler as indicated in the Boiler Installation Instructions.

The wiring diagram for the Unvented Cylinder Zone Valve on an `S Plan`is on this webpage on Megaflow Unvented Hot Water Cylinders:

Megaflo Unvented Direct & Indirect Hot Water Cylinders



I hope that You can get further advice on this from the extremely Expert and Professional Members on here - BUT - PLEASE remember the situation regarding the Cylinder Zone Valve being wired to the Cylinder Thermal Cut Out / High Limit Thermostat.


I hope that this is of some help.


Regards,


Chris


P.S. Who is the Manufacturer of the Unvented Hot Water Cylinder and the Model ?

High Tower said:

Don't be disheartened mate, your posts are always really informative, helpful and to the point, it's priceless having you around to help on these kind of questions.

To the OP, I would question the design with the installer and ask him to provide you with a wiring diagram for the system.

Click to expand...

"Hello High Tower",

Thanks very much for the compliment - it is always nice to feel that what I write is appreciated - especially when that appreciation comes from a `Fellow Professional` such as You and other Members of the Electrical Profession.


I have now been replied to by feebs 73 and as You can see the thread is `Ongoing` - awaiting the input required to adapt the Wiring Diagram that I attached above to an ` S Plan Plus` with the Unvented Cylinder`s Thermal Cut Out / High Limit Thermostat wiring.

The wiring for the Underfloor Heating Controls may have to be seperate from the S Plan Plus wiring plan ? - because it needs to be able to operate `independantly` of the other Zones of the Heating System.

Also the Pump wiring being connected `via` the Boiler IF a Pump Over-run is required [?].

Regards,

Chris

Hi again Chris
I have just read that last thread. I have taken on board what you have said, I can see the diagram but I don't see that third zone valve ( safety valve) I hope I have read and under stood your message correctly as I can see a lot of time and effort has been put in to the reply, I would like to thank you for taking so much time in replying to me, I find this website very informative and have a good read though some of the threads, I guess we never know every thing and we are always learning.
Thanks feebs 73

feebs73 said:

Hi again Chris
I have just read that last thread. I have taken on board what you have said, I can see the diagram but I don't see that third zone valve ( safety valve) I hope I have read and under stood your message correctly as I can see a lot of time and effort has been put in to the reply, I would like to thank you for taking so much time in replying to me, I find this website very informative and have a good read though some of the threads, I guess we never know every thing and we are always learning.
Thanks feebs 73

Click to expand...

"Hello again feebs 73",

The attached Diagrams [Screenshot] are of an `S Plan PLUS` which shows TWO Heating Zone Valves and a Cylinder Zone Valve - as these are Screenshots You might want to use the Snipping Tool to create am image that You can Enlarge - when I found the Colour version I did not know how to delete the Black and White Diagram.

I did look for an S Plan Plus wiring diagram in the Central Heating section where there were some Heating Wiring Diagrams [in PDF form ?] very kindly posted by a Member / Moderator but they seem to have disappeared [?].


Here is a Link to a Honeywell Wiring Plans webpage for the `S Plan Plus` wiring method:

Sundial S Plan Plus - Honeywell UK Heating Controls



Please get confirmation from the Electrical Professionals on here on how exactly to adapt this to include the Unvented Hot Water Cylinder `Thermal Cut Out` / High Limit Thermostat wiring.

The Unvented Cylinder`s Hot Water Thermostat AND the Thermal Cut Out Thermostat are usually a combined unit - so it may be that the wiring would go to the same wires / terminals on the `Wiring Centre` / Terminal Block as is shown on the Diagrams for the conventional Cylinder Thermostat - ?


Although as there are more terminals shown in the Heatrae Sadia Megaflow wiring Diagram - this would have to be clarified by an Electrical Professional - it might be that You would still be able to use a `10 Way` Terminal Block ?.

IT IS VITAL THAT THIS IS WIRED CORRECTLY - THESE ARE ONLY MY SUGGESTIONS - YOU MUST GET EXPERT ELECTRICAL ADVICE ON THIS BEFORE CARRYING OUT THE WIRING FOR THE UNVENTED HOT WATER CYLINDER.


ALSO the wiring for the Underfloor Heating needs to be identified and described how it should be connected - as I previously mentioned this would probably be wired seperately from the `S Plan Plus` [?].



I was trying to explain in My previous message that the Wiring Diagram example is for an `S Plan` - TWO Zone Valves - One Zone Valve for the Heating and One Zone Valve for the Unvented Cylinder.

I attached the Wiring Diagram on My other message so that You and the other Members could see the `Thermal Cut Out` / High Limit Thermostat wiring `TO` the Unvented Cylinder`s Zone Valve - That is the `Additional / Safety Protection wiring that is necessary for the `Safety / Thermal Protection` of the Unvented Hot Water Cylinder.

It is that wiring from the High Limit Thermostat on the Unvented Cylinder that turns the Cylinder Zone Valve into the Unvented Cylinder `Safety Zone Valve` in the event that the High Limit Thermostat operates and interrupts the power to the Zone Valve - Closing it via the `Spring Return` and preventing further Heating of the Hot Water.


Where there are more than TWO Zone Valves on a Heating / Hot Water System the Wiring Plan is called an `S Plan PLUS` - as in Your question and the Wiring Diagram above.


What we now need is for an Electrician / Electrical Engineer to adapt and explain the `S Plan PLUS` wiring diagram [as above] to show the THREE Zone Valves - TWO for the Heating Zones that are controlled by the Room Thermostats [First and Second Floors in your system ?] and ONE Zone Valve for the Unvented Cylinder AND:

Also ADD the wiring for the THERMAL CUT OUT THERMOSTAT ON THE UNVENTED CYLINDER / Hot Water Thermostat.

AND the Underfloor Heating Zone / Controls - which may be seperate from the S Plan Plus ?

I also mentioned that it may be required that the Pump wiring goes `via` the Boiler because there may be a Pump Over-run - this would mean that the Boiler also needs a Permanent Live supply to achieve this - which is another alteration to the `S Plan Plus` wiring plan - there is a segment on the Black and White S Plan Plus Diagram regarding that.


THIS MIGHT BE A `BIG ASK` TO HAVE SOMEONE FULLY EXPLAIN THIS TO YOU [?].


To help with this You should find out whether the Boiler does require a Pump Over-run and also find out what Controls are being used on the Underfloor Heating - and obtain the Underfloor Heating Wiring Diagram.


I hope that I have made this a bit clearer with these details - I know that My previous VERY Long message AND THIS have probably been a bit `daunting` to wade through - But believe it or not I was actually trying to write as `Brief` an explanation as possible !

However I needed to write ALL that I posted in these messages in order to `Fully Explain` - Sorry that it does not seem to have worked out that way from Your point of view.

Please don`t be offended by My use of Red / Blue / Highlighted Text - I am trying to emphasise what I perceive to be the Important points - it also helps Me when I am composing the Messages to see IF I have covered the Important points.


Regards,


Chris - Heating Engineer


P.S. You can see from My lack of Electrical Terminology that I am NOT an Electrician !

The easiest way of wiring in the UFH is just to treat it as a third zone in the heating. So assuming this underfloor heating is just one zone you would take a live (and poss a neutral) to a programmable room stat, take the switched live (and neutral) back to a 2 port zone valve; this operates the motor of the zone valve. Then all you have to do is connect the grey and orange,(the switch inside the valve) in parallel with the grey and orange of the other valves.

Post 13 advised of tthe Splan plus, then in post 14 OP comes back and says no its not.

Think we're on a merrygoround here.

JD Hogg said:

The easiest way of wiring in the UFH is just to treat it as a third zone in the heating. So assuming this underfloor heating is just one zone you would take a live (and poss a neutral) to a programmable room stat, take the switched live (and neutral) back to a 2 port zone valve; this operates the motor of the zone valve. Then all you have to do is connect the grey and orange,(the switch inside the valve) in parallel with the grey and orange of the other valves.

Click to expand...

"Hello JD Hogg",


Underfloor Heating which is installed on the whole of a Ground Floor is often required to be used without the Radiator circuits of the Heating System - especially if those are on the First and Second Floor of the Home / Property.

This would mean that it should usually have its own Timeswitch - not a Programmable Room Thermostat - because as I am sure You know the Thermostatic Control of the Mixing Valve and the various Zones / Rooms within the Ground Floor [for example] are controlled completely seperately from the rest of the Heating System with Room Thermostats which control Actuators on the various Zones on the Underfloor Heating Pipework Manifold.

The Room Thermostats controlling the Underfloor Heating Zones obviously CAN be the Programmable type.


If the Underfloor Heating was wired as You described how would what I have described operate ?


Although people could turn down the other Room Thermostats - in this case for the First and Second Floor Radiator circuits - If Programmable Room Thermostats were installed - as is becoming more popular - that would not really be an option - because of having to lower the Set Temperature by the use of buttons - too much `messing about` for what is supposed to be a `Fully Controllable` Home Heating System.

I do NOT claim to know how to wire the Underfloor Heating - but I know how it is meant to be able to operate.

Regards,


Chris - Heating Engineer

Chris, as I said in my post "assuming this underfloor heating is just one zone". If the OP has a specific system which he would like a wiring diag for I would be happy to help. I have designed and installed many UFH systems some with simple controls as I described and others with more complex controls as you have mentioned.

JD Hogg said:

Chris, as I said in my post "assuming this underfloor heating is just one zone". If the OP has a specific system which he would like a wiring diag for I would be happy to help. I have designed and installed many UFH systems some with simple controls as I described and others with more complex controls as you have mentioned.

Click to expand...

"Hello JD Hogg",


The Underfloor Heating in this case is for the whole Ground Floor as I read it a few Days ago.

In Theory it could be said to be `One Zone` in respect to the fact that it will be supplied from One Zone Valve connected DIRECTLY to the Heating System Flow - NOT from a `Leg` of the Heating System.

But within the Underfloor Heating for the whole Ground Floor there will obviously be Zones / Room Circuits which will have to be controlled by their own Room Thermostats - connected to Actuators on the Underfloor Heating Distribution Manifold.


That is why I have been mentioning that I feel it will probably have to be wired `seperately` from the S Plan Plus wiring plan.


Obviously the Underfloor Heating will have to be supplied via a Two Port Zone Valve connected directly to the Heating System Flow Pipe and there will have to be Timed Control of the Flow to the Underfloor Heating and a `Boiler Interlock` from the Timeswitch / Zone Valve etc. - there will also be a seperate Pump for the Underfloor Heating.


We were not speculating on how to wire the Controls for a fictitious Underfloor Heating System - I was writing about THIS Underfloor Heating System - `Underfloor Heating for the Ground Floor` - this will obviously have Zones within it for various Rooms / Areas.

I don`t want to come across as argumentative - But You did not write about how to Wire / Control the Underfloor Heating System in THIS thread.

I would not have expected a reply about the Underfloor Heating until there are more details from the OP / feebs 73 on exactly what is being installed regarding the Controls etc.

I kept mentioning it because it is a factor in the overall Heating System and specifically the wiring is part of the OP`s Electrical Works.


I am sure that You are very expert in designing wiring plans for Underfloor Heating Systems - But You may not have read the detail that the Underfloor Heating in THIS thread is for the whole Ground Floor of the property.


Regards,


Chris - Heating Engineer