Required valve setup

[TonyS65]

Hello, I currently have a pressurised cylinder with immersion heater powered by solar panels that provides hot water throughout except one sink. I have a combi boiler which supplies that sink and the central heating and helps top up the hot water whilst it’s dark.
I am just installing a new bathroom and want to run it off the pressurised cylinder but when the hot water runs out press a switch that operates a valve/s and supply comes from the combi rather than waiting for the S plan to heat the cylinder water 🤔🤔😂
Any ideas anyone please ??
Thanks in advance.

 

[ShaunCorbs]

Tbh waste of time to even think of trying / how to implement that

 

[TonyS65]

Tbh waste of time to even think of trying / how to implement that

Why would it be a waste of time? I have free hot water via solar/immersion/cylinder, when that runs out after my daughter has been in the bath and I want a shower whilst it’s dark I normally have to wait an hour for the immersion and boiler to reheat.
If I can fit a valve/s to close the cylinder circuit and simultaneously open the boiler circuit then I’m not wasting my time waiting to get a hot shower 🤷‍♂️😊
[automerge]1585990721[/automerge]

Why would it be a waste of time? I have free hot water via solar/immersion/cylinder, when that runs out after my daughter has been in the bath and I want a shower whilst it’s dark I normally have to wait an hour for the immersion and boiler to reheat.
If I can fit a valve/s to close the cylinder circuit and simultaneously open the boiler circuit then I’m not wasting my time waiting to get a hot shower 🤷‍♂️😊

I’ve just been looking on amazon and I’m thinking a two port valve on each hot water output(cylinder no /combi nc ) linked to a two way switch and a non return valve after each two port valve which then meet at a’T’ to supply the shower?
[automerge]1585991545[/automerge]

Why would it be a waste of time? I have free hot water via solar/immersion/cylinder, when that runs out after my daughter has been in the bath and I want a shower whilst it’s dark I normally have to wait an hour for the immersion and boiler to reheat.
If I can fit a valve/s to close the cylinder circuit and simultaneously open the boiler circuit then I’m not wasting my time waiting to get a hot shower 🤷‍♂️😊
[automerge]1585990721[/automerge]

I’ve just been looking on amazon and I’m thinking a two port valve on each hot water output(cylinder no /combi nc ) linked to a two way switch and a non return valve after each two port valve which then meet at a’T’ to supply the shower?

Or a Rega 3 way diverter valve where AB would be shower feed A cylinder supply and B combi supply ? Would either above work?

 

[oz-plumber]

If, under your circumstances, you have to wait for and hour for the cylinder to re-heat, I would just plumb the bathroom directly off the combi.
By the time you buy valves, plumb them and wire them with switches, your return on investment would be years.

 

[TonyS65]

If, under your circumstances, you have to wait for and hour for the cylinder to re-heat, I would just plumb the bathroom directly off the combi.
By the time you buy valves, plumb them and wire them with switches, your return on investment would be years.

I get what you’re saying, I’m looking at £65 for a Rega or £100 for 2ports and non returns plus about a tenner on each for consumables plus my time which at the moment I’ve got at least another three weeks off 😐I can’t see it taking that long really.

 

[Stigster]

By the time you buy valves, plumb them and wire them with switches, your return on investment would be years.

Some people want convenience or options rather than looking to recoup any investment on systems.

Anyway I agree with you on plumbing the bathroom into the combi. This kind of switching of hot supplies OP wants to do is simply not really done as there are other better solutions like yours, giving the bathroom an on-demand supply or fitting an electric shower.

If Tony really wants to do this then of course it can be done. However I'm not so sure that 2-port valves would seal against mains pressure in the long run even if they do work to begin with. If he was to go ahead with this system, what are everyone's thoughts on the motorised valves?

 

[ShaunCorbs]

I get what you’re saying, I’m looking at £65 for a Rega or £100 for 2ports and non returns plus about a tenner on each for consumables plus my time which at the moment I’ve got at least another three weeks off 😐I can’t see it taking that long really.

cant use port valves have to use high flow solenoid valves as there rated for mains pressure

a controller inter locked so only one supply can be used

also two backflow devices due to cross flows

doesnt the cylinder have two coils eg one solar and one heating?

 

[Stigster]

cant use port valves have to use high flow solenoid valves as there rated for mains pressure

Further to my edit which I don't think you would have seen yet, you answered my question about the suitability of 2-port motorised valves working on mains pressure. I did not think they would work.

 

[TonyS65]

Some people want convenience or options rather than looking to recoup any investment on systems.

Anyway I agree with you on plumbing the bathroom into the combi. This kind of switching of hot supplies OP wants to do is simply not really done as there are other better solutions like yours, giving the bathroom an on-demand supply or fitting an electric shower.

If Tony really wants to do this then of course it can be done. However I'm not so sure that 2-port valves would seal against mains pressure in the long run even if they do work to begin with. If he was to go ahead with this system, what are everyone's thoughts on the motorised valves?

The cylinder already has a non return after the hot outlet which stops mains pressure pushing hot water out of the tundish, after that outlet I would fit a motorised valve and then another non return to protect against any feedback from the combi. The combi would have the same fitted and linked together to feed the shower with valve switching no/nc via a two way switch?

 

[TonyS65]

cant use port valves have to use high flow solenoid valves as there rated for mains pressure

a controller inter locked so only one supply can be used

also two backflow devices due to cross flows

doesnt the cylinder have two coils eg one solar and one heating?

One coil from heating circuit and immersion heated no input from panels fluid wise, I think I had the non return covered if that’s what you mean by backflow ?

 

[Stigster]

The cylinder already has a non return after the hot outlet which stops mains pressure pushing hot water out of the tundish, after that outlet I would fit a motorised valve and then another non return to protect against any feedback from the combi. The combi would have the same fitted and linked together to feed the shower with valve switching no/nc via a two way switch?

You will still have mains pressure against one valve or the other, check valve or not. Ordinary 2-port valves will let by under those conditions.

As Shaun said, you'll have to use high flow solenoid valves as they are rated for mains pressure.

 

[Scott_D]

Are 2 ports Wras approved?

 

[ShaunCorbs]

I would say converting the system to a hot water priority would be the best way heated off the combi boiler
[automerge]1586003735[/automerge]

Are 2 ports Wras approved?

no and I believe some of the cheaper ones still have some lead in the make up

 

[TonyS65]

You will still have mains pressure against one valve or the other, check valve or not. Ordinary 2-port valves will let by under those conditions.

As Shaun said, you'll have to use high flow solenoid valves as they are rated for mains pressure.

Thanks for the clear up on that matter and that’s why I’ve come on here, I’m good with the idea in my head but as far as the technical abilities of the valves are concerned I’m a bit naive which would end up costing me.
Thanks.

 

[Scott_D]

What about a simple bypass with lever valves. Similar to what you fit with a water softener

 

[TonyS65]

What about a simple bypass with lever valves. Similar to what you fit with a water softener

I’m open to any suggestion, do you mean like a ball isolation valve? One on each supply ; turn one off then the other on ?

 

[Scott_D]

https://www.thewatersoftenercentre.com/images/bypassed2.jpg

You could send the ‘warm’ to be heated by the combi provided it’s compatible.

 

[ShaunCorbs]

What about a simple bypass with lever valves. Similar to what you fit with a water softener

problem is you have an unregulated supply eg no prv so you would need to install a prv on the main and set it up to the correct spec

 

[TonyS65]

problem is you have an unregulated supply eg no prv so you would need to install a prv on the main and set it up to the correct spec

If I remember back a year or two ago I’m sure there is an incoming PRV as we have an average of 110-120 psi which would probably have caused problems unregulated?

 

[Brambles]

Tony,

To do that ie. feed a shower from either an unvented or combi supply you should use a three port L Port solenoid valve that is WRAS approved.

The valve is mounted as close as possible to the shower hot input - with the twin feeds (unvented and combi) feeding directly into the L Port valve.

Control of the valve is through a solenoid - which would normally be 12V or 24V for use in a bathroom / wet room environment.

Don’t be tempted to use a 3 Port T valve - they will not give an effective seal between the ports - they are intended for single entry, twin exit ports, where minor leakage across the outputs is not an issue.

A three port L valve will not start to open the second entry port until the first entry port is fully closed.

I think that Regulations would also require you to fit an RPZ valve on the unvented feed to the three port L valve. Others more familiar with the regulations could probably give better advice on that aspect.

Suitable three port L valves in 3/4 bore are available from Albion - circa £150.

It is not a difficult concept to configure, but obviously you have to instal a second run of 22mm DHW up to the shower installation.

Personally, I would make the switching point at the first point of DHW exit from the UV cylinder, where you could use a 240v actuator - albeit the cost of the valve is the same.

One final point - ensure that you configuration ( if not mounted adjacent to the shower) has no potential to back feed any balanced cold supply.

Good luck with your project

 

[TonyS65]

Tony,

To do that ie. feed a shower from either an unvented or combi supply you should use a three port L Port solenoid valve that is WRAS approved.

The valve is mounted as close as possible to the shower hot input - with the twin feeds (unvented and combi) feeding directly into the L Port valve.

Control of the valve is through a solenoid - which would normally be 12V or 24V fir use in a bathroom / wet room environment.

Don’t be tempted to use a 3 Port T valve - they will not give an effective seal between the ports - they are intended for single entry, twin exit ports, where minor leakage across the outputs is not an issue.

A three port L valve will not open the second entry port until the first entry port is fully closed.

I think that Regulations would also require you to fit an RPZ valve on the unvented feed to the three port L valve. Others more familiar with the regulations could probably give better advice on that aspect.

Suitable three port L valves in 3/4 bore are available from Albion - circa £150.

Good luck with your project

Thanks for your in depth advice, I’ll search for the parts and get advice regarding the regs beforehand 😊

 

[Stigster]

Thanks for your in depth advice, I’ll search for the parts and get advice regarding the regs beforehand 😊

Brambles is "The Man" when it comes to informative and detailed explanations and answers. It is quite apparent over multiple posts that he knows what he's on about. Much respect.

Sorry to go slightly off topic, I just thought that needed saying right now for some reason.