Two zone valves working opposite ways

G

Goldspoon

Is it possible to wire two two port valves to the same cylinder thermostat so A opens and B closes when water temp reaches 60 degrees? In reverse it would be when water temp drops below 60 then A closes and B opens.

Thanks :)

What I am trying to do is to get a combi hot water supply pipe to open if a cylinder of water drops its temperature...
 
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never done what your doing before but as with a honeywell v4043h is normally closed with no power on valve.

a honeywell v404b will be open with no power on valve.
so using both these valves will do what you want
one open other closed etc.
 
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yes it is easy to do we do it all the time with solar /combi systems
it is used to bypass the combi when cylinder is hot enough

cylinder stat has a normally open and a normally closed wire 1 zone valve to each
or alternative is to buy a Normally open valve and a normally closed valve and wire to same terminal on cylinder stat
(honeywell make both types)
 
G

Goldspoon

Thank you both very much indeed - am doing a job next week where we are fitting a wood burner and cylinder. Needed a method of switching between cylinder and combi and levers were being discussed - sounded rather Heath Robinson to me so this will do nicely.

Best place to buy these valves?
 
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plumb center usually have both in 22mm and 28mm

remember to install so in the event of power failure the system is safe to use (bypassing the heating source)
 
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It seems strange to switch it all around 60c. With no dead band you could end up with regular switching of valves if the water temp hangs around 59 to 61c.

In industry we would normally design the system to switch with a dead band of 5 to 10 degree c to minimise to possibility of cyclic switching and maximise the working life of any moving parts.

Would this design not also be used in the domestic side ?
 
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You won't be able to put any form of control on the hot water side from the wood burner.

This would have to be plumbed via what is called a neutraliser, I think.

The wood burner cannot respond (shut off) when the cylinder is up to temp quickly enough.

Or perhaps I have the wrong end of the stick :oops: :confused:
 
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yes it is easy to do we do it all the time with solar /combi systems
it is used to bypass the combi when cylinder is hot enough

How does that work on the DHWS side?

Are the combi and cylinder fed from a tank, or the cylinder would have to be unvented?
 
G

Goldspoon

It seems strange to switch it all around 60c. With no dead band you could end up with regular switching of valves if the water temp hangs around 59 to 61c.

In industry we would normally design the system to switch with a dead band of 5 to 10 degree c to minimise to possibility of cyclic switching and maximise the working life of any moving parts.

Would this design not also be used in the domestic side ?

Good point. Not sure why I said 60 as it can be any figure. More likely will use 45 or a figure just hot enough for showering.



The cylinder is vented and there is a heat sink in place (both not shown). There are also a coupla non-return valves not shown. I am just interested in the hot water supply.
 
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who drew that? Homer Simpson?
Direct connection between cold mains and tank fed supply :cry:
Check with the local water authority to see what they think of it.
Bet you dont.
 
G

Goldspoon

Are you taking the mickey because there's no ball valve?

Top left corner is a CWSC. The ball valve is not shown if that's what you mean - 'tis just a simple diagram not meant to guide one on how a cistern operates.

Unless you mean something else?
 
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Are you taking the mickey because there's no ball valve?

Top left corner is a CWSC. The ball valve is not shown if that's what you mean - 'tis just a simple diagram not meant to guide one on how a cistern operates.

Unless you mean something else?

He means something else.
There is so much wrong with that, it beggars belief.
 
G

Goldspoon

Okay inform me...

I'm working with a Hetas chap and he'll be doing the job (I'm just there to help out)... just trying to think of a different way of doing things...
 
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I don't think you'll have much luck with using a v4043 to hold back the mains pressure from the combi.
 
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It appears to me that you will then only use the cylinder when it is up to maximum temperature? So your hardly ever going to use the cylinder. The whole idea is flawed I'm afraid. Why not use the heating side of the combi to top up the cylinder via a 3rd coil and forget the combi hw supply.
Personally I'd say your best option would be a Thermal Store. Wheres Big Burner when you need him
:LOL:
 

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