Safety zone valve to cylinder

[feebs73]

Help
Is there anybody out there that can point me in the write direction for a wiring diagram for a cylinder safety zone valve, i am stuggling to find any diagrams on this, i find it hard to belive that this saftey valve system is hard to find as this is apparently very important to stop a pressurised cylinder blowing.
feebs 73

 

[Megavolt]

Help
Is there anybody out there that can point me in the write direction for a wiring diagram for a cylinder safety zone valve, i am stuggling to find any diagrams on this, i find it hard to belive that this saftey valve system is hard to find as this is apparently very important to stop a pressurised cylinder blowing.
feebs 73

What unvented cylinder is it. You basically need to interrupt the zone valve supply via the cylinders high limit stat

 

[feebs73]

Hi Elrick
I dont know of the top of my head about the cylinder, i think it is a builder center's own brand it is about 5ft tall with a single immersion element, do you have a wiring diagram on how it is incorporated in the 1-10 choc block.
Many thanks
Feebs73

 

[Megavolt]

Best I can do read around page 11. Put will change depending on make and model

http://www.plumbcenter.co.uk/wcssto...all/ti/on/Center_Centerstore_Installation.pdf

 

[feebs73]

Thanks again
Just had a look at that link, I can see the basic wiring diagram but not one incorporating that 3rd valve.
Thanks once again
Feebs 73

 

[JD Hogg]

You don't need 3 zone valves. You just need to wire the hot water tank zone valve supply in series with the tank stat. You only need a safety zone valve if you are using a Y plan system (i.e a mid position valve or three port valve), in this case the 2 port zone valve is connected in the primary flow to the hot water cylinder and again the zone valve supply is wired via the tank stat.

 

[feebs73]

Ok thanks for that jd hogg,

 

[Megavolt]

You don't need 3 zone valves. You just need to wire the hot water tank zone valve supply in series with the tank stat. You only need a safety zone valve if you are using a Y plan system (i.e a mid position valve or three port valve), in this case the 2 port zone valve is connected in the primary flow to the hot water cylinder and again the zone valve supply is wired via the tank stat.

Tank stat or high limit stat two completely different things

 

[JD Hogg]

It's simple really, the unvented cylinders come as a package with everything you need so if you use all the bits and everything is installed correctly all should be well. For the majority of packages you would get one thermostat called a dual stat which is in fact a combined high limit stat and tank stat (control stat). You would only use a seperate high limit stat if you were installing a dual fuel cylinder e.g. solar or a Y plan system.

 

[Amp David]

Ok thanks for that jd hogg,

Sure this was answered in the in the other post, but never mind.

Who ever has done the plumbing must of made sure that the 2 port valve for the hot water is positioned between the cylinder and blow off/expansion pipe that goes into the tank in loft.





(description of said pipe may be wrong lol).

 

[JD Hogg]

Sure this was answered in the in the other post, but never mind.

Who ever has done the plumbing must of made sure that the 2 port valve for the hot water is positioned between the cylinder and blow off/expansion pipe that goes into the tank in loft.





(description of said pipe may be wrong lol).

Unvented cylinders don't have such a pipe

 

[Amp David]

Thought we were on about vented sorry, go mixed up with his other thread

 

[chris murphy]

Help
Is there anybody out there that can point me in the write direction for a wiring diagram for a cylinder safety zone valve, i am stuggling to find any diagrams on this, i find it hard to belive that this saftey valve system is hard to find as this is apparently very important to stop a pressurised cylinder blowing.
feebs 73

"Hello feebs 73",


I have posted another message in answer to You about this on the original thread here:

http://www.electriciansforums.net/c...ntral-heating-3-zone-valves-2.html#post637425

Some of the Members on this thread have got the correct idea about the `Thermal Cut Out` / High Limit Thermostat being wired to interupt the power to the TWO Port Zone Valve and therefore Close it in the event of the High Limit Thermostat having to operate.

Please also read My reply to Amp David below and then please go to My reply to You on the original Topic [Link above].


I have gone into quite a lot of detail in My latest message to You on that thread - but what I have posted needs adding to in order to accommodate the requirements of the Unvented Hot Water Cylinder and the Heating Zones - plus the Underfloor Heating Controls.

THAT is definitely beyond My capabilities to `design` and explain to You - one of the Electrical Expert Members should be able to adapt the Diagram that I have posted to an `S Plan PLUS` and add the additional wiring for the Underfloor Heating Controls.



Regards,


Chris - Heating Engineer

 

[chris murphy]

Sure this was answered in the in the other post, but never mind.

Who ever has done the plumbing must of made sure that the 2 port valve for the hot water is positioned between the cylinder and blow off/expansion pipe that goes into the tank in loft.





(description of said pipe may be wrong lol).

"Hello Amp David",


The Unvented Cylinder Zone Valve must be a Two Port Valve - `Spring Return closing` [Usually supplied by the Unvented Cylinder Manufacturer] - and is installed on the Flow to the Unvented Hot Water Cylinder.

As well as being wired in an `S Plan` for the Heating and Hot Water System Controls there MUST be wiring from the Unvented Cylinder`s Thermal Cut Out / High Limit Thermostat which interrupts the power to the Zone Valve in the event that the Thermostat operates - thus allowing the Zone Valve to return to the Closed position [Spring Return].

This stops the Heat from circulating around the Cylinder Coil and further increasing the Temperature of the Domestic Hot Water and the possible over-pressurisation of the Unvented Cylinder - IF the Temperature and Pressure Relief Valve malfunctioned and did NOT discharge the over pressure.

If You want to read My VERY long message to feebs 73 about this I have posted a Link to the original Topic in My reply to Him above.

I have attached a Diagram of an EXAMPLE of the wiring for a Heatrae Sadia Megaflow Unvented Indirect Hot Water Cylinder in case anyone else is interested in this.

Obviously people should refer to the EXACT wiring Diagram for the Unvented Hot Water Cylinder that they are wiring and NOT take it for granted that this would be correct for ALL Unvented Cylinders.


Regards,

Chris - Heating Engineer

 

[Amp David]

CHeers Chris,


It was my mistake, thought he was originally on about a vented system.

Totally see what you mean in the above post though

 

[chris murphy]

Hi Elrick
I dont know of the top of my head about the cylinder, i think it is a builder center's own brand it is about 5ft tall with a single immersion element, do you have a wiring diagram on how it is incorporated in the 1-10 choc block.
Many thanks
Feebs73

"Hello again feebs 73",

JUST to make sure that You are asking about an `INDIRECT` Unvented Hot Water Cylinder - regarding your description above [which I have just noticed] - have I been correct in My assumption that there IS a Flow and Return from the Heating System connected to the Unvented Cylinder to Heat the Hot Water via the Cylinder Coil ?

I have been answering You on that assumption because it would be impossible to Heat an Unvented or a Vented Cylinder to meet the needs of a property with `3 Ensuite Bathrooms / Shower Rooms` using an Immersion Heater - unless the Bathing / Showering was being done at different times for each Bathroom.

Even with the Flow and Return from the Boiler it might not be capable of `recovering` the Hot Water temperature quick enough for perhaps 3 consecutive Showers [?] - But that is not your problem.

I assume that You just mean that it ALSO has an Immersion Heater fitted - But will primarily be Heated by the Boiler / Heating Flow and Returns ?

IF NOT - then I have written a LOT of `Non Applicable` Information in My replies to You !


Regards,


Chris

 

[feebs73]

Hi chris
the 5 bedroom 3 ensuite job was a different one to the origanal posting regarding the 3rd zone valve( safety valve), I was just asking about the 5 bed job because in my eyes it is the same s plan just on a bigger version than the origanal post, but does not have the safety valve that has been mentioned before.
many thanks feebs73

 

[chris murphy]

Hi chris
the 5 bedroom 3 ensuite job was a different one to the origanal posting regarding the 3rd zone valve( safety valve), I was just asking about the 5 bed job because in my eyes it is the same s plan just on a bigger version than the origanal post, but does not have the safety valve that has been mentioned before.
many thanks feebs73

"Hello again feebs 73",


Sorry that I misunderstood Your Post on this thread - I thought that You were just trying to get the information by rewording the question.

I am a bit confused by the title of THIS thread - `Re: Safety zone valve to cylinder` - what are You asking about HERE ?


Also did You read My VERY Long message to You on the `other` thread about the `Safety / Thermal Cut Out`wiring / and example Wiring Diagram for the Unvented Cylinder`s Zone Valve ?


Regards,

Chris

 

[chris murphy]

You don't need 3 zone valves. You just need to wire the hot water tank zone valve supply in series with the tank stat. You only need a safety zone valve if you are using a Y plan system (i.e a mid position valve or three port valve), in this case the 2 port zone valve is connected in the primary flow to the hot water cylinder and again the zone valve supply is wired via the tank stat.

"Hello JD Hogg",

On an Unvented Indirect Hot Water Cylinder the Two Port Zone Valve operation MUST also be wired to the Thermal Overheat Thermostat / `High Limit Thermostat` fitted to the Unvented Cylinder - If this ever operates it interupts the power to the Zone Valve which then closes via the spring return.

This obviously stops the Heat circulation to the Unvented Cylinder Coil and prevents further Overheating and possible Over-pressurisation of the Unvented Cylinder in the event that the Pressure and Temperature Relief Valve malfunctioned and did NOT release the Over-pressurisation - which although unlikely is possible.

Regards,

Chris - Heating Engineer

 

[chris murphy]

Hi chris
the 5 bedroom 3 ensuite job was a different one to the origanal posting regarding the 3rd zone valve( safety valve), I was just asking about the 5 bed job because in my eyes it is the same s plan just on a bigger version than the origanal post, but does not have the safety valve that has been mentioned before.
many thanks feebs73

"Hello again feebs 73",


Have You seen My latest messages to You on the other thread ?

Also - having read your comment above - is the Underfloor Heating in the same property as the Unvented Hot Water Cylinder / `3 Zones Valves` thread that We have been corresponding about ?

If not - I feel that You confused matters when You mentioned the description about the `5 Bedroom - 3 Ensuites - Underfloor Heating to the Ground Floor` etc. during the correspondence about the Unvented Hot Water Cylinder / `3 Zone Valves` thread - although obviously unwittingly - I thought You were describing the Job that We were writing about ?

Until NOW [having read your comment above] I have thought that this was the SAME Job / Heating System / Wiring enquiry - ?


What I have written on the ORIGINAL thread about the S Plan Plus and the Thermal Protection / `High Limit Thermostat of the Unvented Hot Water Cylinder would still be fully applicable - BUT - I have been involved in a slight `debate` with another Member about the `Ground Floor Underfloor Heating` being wired seperately to the S Plan Plus wiring plan.

IF it is NOT installed in the property that we first started corresponding about I would NOT have kept mentioning it and trying to elicit responses including the wiring for that on Your behalf from the other Members.

Could You please clarify this point - "Thanks".


Regards,

Chris

 

[feebs73]

Hi Chris
This is my fault, yes there are two jobs that i am talking about
1, is the standard s plan with the extra zone valve (on the hw) fitted to the cylinder, ( so called safety valve) this one is causing the debate.
2, this is another job I have to wire up this is a s plan plus,3 storey house, ground floor is UFH 1st floor has a separate zone valve and stat , 2nd floor has a separate zone valve and stat,

The confusion is I was asking, as they are both s plans pressurised systems, I was woundering why job 2 has not got 2 zone valve attached to the cylinder just the 1, when I asked the plumber he said no you only fit them on a mid position valve Y plan. He than showed me the ( forgive me but It looks like a over flow witch had 2x15mm pipe into 2inch plastic waste pipe) and said that deals with any excess pressure.

I was asking for help as I have never come across this extra zone valve on the hw system (safety valve) before if it is such an important part of the install why cant I find it on any wiring diagram? I would of thought it would of been easy to find it. Even the diagram you posted didn't have the extra have it on there.

I started the other thread to see if I could catch anyone's attention, sorry for the confusion.

I hope this clears things up a bit

I would like to thank everyone personally that is taking time to read these threads and replying to me

Thanks once again all the advise is much appreciated, feebs73

 

[feebs73]

Hi Chris
This is my fault, yes there are two jobs that i am talking about
1, is the standard s plan with the extra zone valve (on the hw) fitted to the cylinder, ( so called safety valve) this one is causing the debate.
2, this is another job I have to wire up this is a s plan plus,3 storey house, ground floor is UFH 1st floor has a separate zone valve and stat , 2nd floor has a separate zone valve and stat,

The confusion is I was asking, as they are both s plans pressurised systems, I was woundering why job 2 has not got 2 zone valve attached to the cylinder just the 1, when I asked the plumber he said no you only fit them on a mid position valve Y plan. He than showed me the ( forgive me but It looks like a over flow witch had 2x15mm pipe into 2inch plastic waste pipe) and said that deals with any excess pressure.

I was asking for help as I have never come across this extra zone valve on the hw system (safety valve) before if it is such an important part of the install why cant I find it on any wiring diagram? I would of thought it would of been easy to find it. Even the diagram you posted didn't have the extra zone valve on there.

I started the other thread to see if I could catch anyone's attention, sorry for the confusion.

I hope this clears things up a bit

I would like to thank everyone personally that is taking time to read these threads and replying to me

Thanks once again all the advise is much appreciated, feebs73

Missed a bit sorry

 

[snowhead]

On an unvented installation there must be a 2 port valve, spring assisted fail to closed position, (not motored closed) wired via the cylinder overtemp stat to prevent over heating of the cylinder.

The manufacturer has to provide this as part of the kit supplied with the cylinder, the manufacturers instructions will say a 2 port valve must be fitted.

The confusion arises when the cylinder is piped up.

If the heating system already has a 2 port valve on the flow to the cylinder, as long as this is wired via the overtemp stat on the cylinder and is spring closed, it will comply. 2nd 2 port valve is not required.

If it has a 3 port (mid position) valve there must be a 2 port fitted as well because the 3port can fail open.

Plumbers /heating engineers will sometimes not look at the whole picture and just see that a 2 port has to be fitted close to the cylinder.

Tried to make this a simple explanation, but it won't work.

 

[diditrain]

I have seen a diagram in a pdf but i have not got a clue on how to upload it for you.

Page 6. Might be what you are looking for
http://www.albionwaterheaters.com/pdfs/technical/ultrasteel.pdf

 

[snowhead]

Using the diagram in here;

http://www.plumbcenter.co.uk/wcssto...all/ti/on/Center_Centerstore_Installation.pdf

Fig 8, connect the 2nd 2 port valve in parallel with the zone valve at Junction box terminal 8 (L) and 2 (N)

 

[feebs73]

I have seen a diagram in a pdf but i have not got a clue on how to upload it for you.

Hi diditrain
Can you give the website address or anywhere where you found it
Thanks feebs63

 

[diditrain]

Look at my post 24, website details

 

[feebs73]

Using the diagram in here;

http://www.plumbcenter.co.uk/wcssto...all/ti/on/Center_Centerstore_Installation.pdf

Fig 8, connect the 2nd 2 port valve in parallel with the zone valve at Junction box terminal 8 (L) and 2 (N)

Thanks snowhead
it is a Honeywell zone valve (sorry for my ignorance) but what do I do with the 5th core.
? Do I just choc block it and make safe
thanks feebs73

- - - Updated - - -

Look at my post 24, website details

Got it cheers

 

[feebs73]

Look at my post 24, website details

Thanks diditrain, did you mean the wiring diagram at the top of page 16 if so I only see the one zone valve for the hw side
thanks73

 

[feebs73]

Thanks diditrain, did you mean the wiring diagram at the top of page 16 if so I only see the one zone valve for the hw side
thanks73

I ment page 6 sorry

 

[snowhead]

? Do I just choc block it and make safe
thanks feebs73

Yes you only need L,N,E for the safety valve

 

[chris murphy]

Hi Chris
This is my fault, yes there are two jobs that i am talking about
1, is the standard s plan with the extra zone valve (on the hw) fitted to the cylinder, ( so called safety valve) this one is causing the debate.
2, this is another job I have to wire up this is a s plan plus,3 storey house, ground floor is UFH 1st floor has a separate zone valve and stat , 2nd floor has a separate zone valve and stat,

The confusion is I was asking, as they are both s plans pressurised systems, I was woundering why job 2 has not got 2 zone valve attached to the cylinder just the 1, when I asked the plumber he said no you only fit them on a mid position valve Y plan. He than showed me the ( forgive me but It looks like a over flow witch had 2x15mm pipe into 2inch plastic waste pipe) and said that deals with any excess pressure.

I was asking for help as I have never come across this extra zone valve on the hw system (safety valve) before if it is such an important part of the install why cant I find it on any wiring diagram? I would of thought it would of been easy to find it. Even the diagram you posted didn't have the extra have it on there.

I started the other thread to see if I could catch anyone's attention, sorry for the confusion.

I hope this clears things up a bit

I would like to thank everyone personally that is taking time to read these threads and replying to me

Thanks once again all the advise is much appreciated, feebs73

"Hello again feebs 73",


Where You seem to be getting confused here is that there are Not TWO 2 Port Zone Valves required on this Unvented Hot Water CYLINDER - Just ONE which is wired to the COMBINED Hot Water Thermostat AND Thermal Protection / `High Limit Thermostat to provide the Thermal Protection of the Unvented Hot Water Cylinder.

This is usually supplied by the Unvented Hot Water Cylinder Manufacturer and is shown in the Installation Instructions for both the Pipework configuration AND the Wiring Instructions / Diagram.

That Cylinder Zone Valve `becomes` the `Cylinder Thermal Safety Valve` if the High Limit Thermostat has to operate and interrupt the POWER to the Zone Valve which will then CLOSE via the spring return - stopping further Heat circulating around the Cylinder Heating Coil and preventing Overheating and possible Over-Pressurisation of the Unvented Hot Water Cylinder IF the Temperature and Pressure Relief Valve were to malfunction in the CLOSED position.


I also wanted to reply to You again regarding a comment from your post:


QUOTE:


I was asking for help as I have never come across this extra zone valve on the hw system (safety valve) before if it is such an important part of the install why cant I find it on any wiring diagram? I would of thought it would of been easy to find it. Even the diagram you posted didn't have the extra have it on there.


END QUOTE


The FIRST Wiring Diagram that I posted for You was for a Heatrae Sadia Megaflow UNVENTED HOT WATER CYLINDER.

On THAT wiring Diagram the WIRING was shown for the Unvented Hot Water Cylinder Thermostat AND `Thermal Protection` / `High Limit` Thermostat TO the Zone Valve for the Unvented Hot Water Cylinder.


I posted that to show You the `Safety / Thermal Protection` WIRING / Zone Valve for the Unvented Hot Water Cylinder.


It is THAT WIRING that turns the Unvented Hot Water Cylinder`s Zone Valve into a `Safety Zone Valve` IF the `High Limit` Thermostat Operates - by interrupting the Power to the Zone Valve and allowing it to CLOSE via the spring return operation.


You are NOT the only person who seems to have either NOT Understood My explanations OR not read them fully as I can see from some other Members Posts - one of which has duplicated exactly what I was trying to explain although in a much shorter version.

IF they HAD seen / understood what I had written I would be wondering why they would write the same information in a post - especially when they did NOT seem to be agreeing with Me / confirming that what I had written was correct - ?


I hope that You can now work out what the requirements are for the `Thermal Protection` aspect of an Unvented Hot Water Cylinder.

As I have written such a LOT in My messages to You could You please let Me know the Manufacturer and Model of the Unvented Hot Water Cylinder that We have been corresponding about - Thanks.


Regards,


Chris

 

[chris murphy]

On an unvented installation there must be a 2 port valve, spring assisted fail to closed position, (not motored closed) wired via the cylinder overtemp stat to prevent over heating of the cylinder.

The manufacturer has to provide this as part of the kit supplied with the cylinder, the manufacturers instructions will say a 2 port valve must be fitted.

The confusion arises when the cylinder is piped up.

If the heating system already has a 2 port valve on the flow to the cylinder, as long as this is wired via the overtemp stat on the cylinder and is spring closed, it will comply. 2nd 2 port valve is not required.

If it has a 3 port (mid position) valve there must be a 2 port fitted as well because the 3port can fail open.

Plumbers /heating engineers will sometimes not look at the whole picture and just see that a 2 port has to be fitted close to the cylinder.

Tried to make this a simple explanation, but it won't work.

"Hello snowhead",


From what You wrote I take it that You did not read My explanations to the OP / feebs 73 about the Thermal Protection / Zone Valve Wiring for an Unvented Hot Water Cylinder - as I had fully explained all that you wrote and I notice that your post was not worded as `in agreement` with what I wrote.

If You had read what I wrote and were posting a `simpler explanation` I would of course understand - But You seem to have written your reply as if I had NOT already explained what you wrote ?


I don`t want to cause an argument here but I wanted to ask You about this comment:


QUOTE:


Plumbers /heating engineers will sometimes not look at the whole picture and just see that a 2 port has to be fitted close to the cylinder.


END QUOTE


I am hoping that You might mean that in the absense of Electrical / Electrical Testing Qualifications and experience a Heating Engineer / Plumber who was just looking at an existing Unvented Hot Water Cylinder might not know whether the WIRING for the Thermal Protection was done correctly - ?


Heating Engineers or Plumbers who `Hold` / `Have attained` ACS Assessment / Certification [& `Unvented Licence Card`] in `Unvented Hot Water Systems` are the ONLY persons who can LEGALLY Install OR `Work On` Unvented Hot Water Cylinders.


That is required by `Part G3` of the Building Regulations - `Hot Water Safety and Water Efficiency` - and as You know these are `Legally Binding` Regulations.

This is a Mandatory requirement for Unvented Hot Water Systems - it is NOT like some other parts of the Building Regulations where Operatives can carry out Works and then Notify them to the Local Authority Building Control Department as either `One Off` projects or as part of a Building Project for LABC Inspection / Certification.



The Electrical Wiring of the Zone Valve and Thermostatic / Thermal Protection for the Unvented Hot Water Cylinder must then be carried out by a Qualified Electrician / `Competent Person` in order to comply with the Building Regulations G3 for Unvented Hot Water Systems.

IF You are implying in your comment that these Heating Engineers /Plumbers are somehow `confused` on the Requirements / Design and Operation of the Thermal Protection for Unvented Hot Water Cylinders that could easily be viewed as Insulting by Professional Heating Engineers like Me.

IF I misunderstood your comment I Apologise - but it did seem that You were suggesting that regarding the Thermal Protection of an Unvented Hot Water Cylinder `Plumbers and Heating Engineers` don`t know exactly what to do regarding the installation of the required Zone Valve .

We would obviously be writing about `Professional` Heating Engineers and Plumbers - NOT the `Cowboys` and I would hope that ALL of the Professional Heating Engineers and Plumbers would KNOW about the Thermal Protection required for an Unvented Hot Water Cylinder.

And that ONLY those who were Registered and Certified for `Unvented Hot Water Systems` would be Installing or Working On Unvented Hot Water Cylinders - obviously I know that it would be very naive to think that this was the case.

When the OP / feebs 73 asked about the Unvented Hot Water Cylinder Zone Valve in this thread there was NOT exactly a `rush` from Electricians / Members to help Him.

I had thought that this was because Members were awaiting further descriptions of the circumstances and that is when I started to Post replies to the OP / feebs 73.

I am sure that the details that I posted were completely correct - except for the confusion about the Underfloor Heating [now found to NOT be part of that Heating and Hot Water System].

I would have thought that what I wrote would have helped the OP / feebs 73 [?] - But I would admit that the Posts were probably be viewed as far too LONG and might have been `off putting` to wade through.

I had hoped that My descriptions of what was required would prompt a detailed description in `Electrical Terminology` for feebs 73 by an Electrician Member.


Regards,

Chris - Heating Engineer and Registered /Certified for
`Unvented Hot Water Systems`