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Safety zone valve to cylinder

Discuss Safety zone valve to cylinder in the Central Heating Systems area at ElectriciansForums.net

F

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
 
feebs73 said:
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
Click to expand...

What unvented cylinder is it. You basically need to interrupt the zone valve supply via the cylinders high limit stat
 
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
 
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
 
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.
 
Last edited:
JD Hogg said:
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.
Click to expand...

Tank stat or high limit stat two completely different things
 
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.
 
feebs73 said:
Ok thanks for that jd hogg,
Click to expand...

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).
 
Amp David said:
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).
Click to expand...

Unvented cylinders don't have such a pipe
 
feebs73 said:
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
Click to expand...



"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
 
Last edited:
[ElectriciansForums.net] Safety zone valve to cylinder
Amp David said:
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).
Click to expand...


"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
 
Last edited:

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