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