Fail safe hot water... Can u foresee any issues with this

[Mbear]

Imagine a combi supplying hw to kitchen only, an unvented cyl supplying bathroom suite and power shower. One kitchen one bathroom, nothing fancy. Now can anyone foresee an issue with this......

The hw pipe supplying the shower has a stopcock fitted inbetween the cyl and the shower, then the combi hw supply going to the shower aswell, again it has a stopcock on it before it finally gets to shower supply pipe. You would use the cyl primarily for the shower hot water (combi stopcock closed&cyl stopcock open), then if the cyl ran cold for any reason for eg faulty zone valve/stat or just back from holidays etc u could turn cyl stopcock off and turn combi stopcock on to instantly supply the shower with hw. Its just an idea I had for my bathroom when I do it up, I want a proper power shower by plumbing in an unvented cyl to the combi but I want the security of instant hw from the combi.

I can't really foresee any issues myself aslong as only one stopcock is opened At any one time. What do u lot think?

 

[mickie]

i cant see a problem as long as they dont mix, but if they did the hot water from the combi would fill the hot tank in the loft untill it started overflowing

 

[Mbear]

i cant see a problem as long as they dont mix, but if they did the hot water from the combi would fill the hot tank in the loft untill it started overflowing

Even though it's an unvented cyl?

 

[mickie]

sorry im getting confused.. that wouldnt happen with unvented

both the unvented and combi work off mains pressure, so it'll be fine, if you forgot the turn your valves off..

if you opened the hot tap water would be drawn from 2 places so its likely you wouldnt get any hot water coming through at all untill it started coming from 1 or the other.. but as long as you keep them apart it'll be fine

 

[marleyco]

When you say power shower do you mean a mixer, pressure would be too great for a power shower. I don't see an issue with your design, although not common practice, you would maybe have to put a non return valve on the hot pipe at boiler, just in case both valves are opened

 

[AWheating]

i think you are thinking of problems that dont need solving. tell the missus she will have to wait for the cylinder to warm up.

 

[Mbear]

Sorry Ye, mixer shower. I suppose putting a check valve before both stopcocks wouldn't be a back idea.

I've planned it out in my head anyway, boiler is in the kitchen, cyl would be in loft directly above boiler, there's a cupboard beside wc. I'd have pipes coming down into cupboard into the stopcocks and back into the loft and finally into shower. This would give ease of switchover wothouth having to enter loft

 

[Mbear]

i think you are thinking of problems that dont need solving. tell the missus she will have to wait for the cylinder to warm up.

We have an elect shower at the min, it's me who wants the pressure of unvented cyl for mixer shiwer and the security of combi. She doesn't care lol aslong as theirs hw available. I've got a combi at the min but I want to add a cyl

 

[marleyco]

It's going to cost a bit more than your normal install, but having 3 ways to get hot water, you won't be worrying. Immersion, heating coil and combi. Patent it

 

[Mike Jackson]

You'd definitely need a check valve on the outlet from the cylinder. If you inadvertantly turned on both valves you'd have unregulated mains pressure running back into the cylinder. PRV would prevent damge to the cylinder but it doesn't help the longevity of the prv if it opens too often.

 

[SimonG]

Depending on mains water pressure the only problem I could see if you failed to shut one valve or the other would be potential to overpressure cylinder and discharge through tundish. The check valves would sort that and you could also fit the prv at incoming stopcock rather than at cylinder.

 

[dancinplumba]

could automate this quite simply with pipestat and 2 port valve.....

 

[Mbear]

It's going to cost a bit more than your normal install, but having 3 ways to get hot water, you won't be worrying. Immersion, heating coil and combi. Patent it

I don't think there would be a great demand for it but I'm sure it wouldn't be too hard to knock up a working prototype that could be made into one multi function brass valve incorporating 2 stopcocks/2 check valves/2 inlets/1 outlet

 

[Mbear]

could automate this quite simply with pipestat and 2 port valve.....

Could a 2port hold mains pressure at bay without passing do u think?

For eg gate valves aren't great at holding mains pressur

 

[marleyco]

Dragons den, lol

 

[Mbear]

Dragons den, lol

Haha, no doubt someone will be along shortly to say that it doesn't conform to some water bye law lol

 

[marleyco]

sput sure stop's in. couple of switches on the wall, then even your wife would manage to swap them

 

[dancinplumba]

Could a 2port hold mains pressure at bay without passing do u think?

For eg gate valves aren't great at holding mains pressur

you have check valves.....

 

[Mbear]

I got asked to fit a sure stop but it turned out to be impossible to turn the mains off, no stopcock in house, all the street Toby's would not shut it off, had to give up in the end. That was 6 yrs ago & even though it was nothing to do with that sure stop it put me off using it again after that experience lol

 

[dancinplumba]

easier to just fit a b igger combi or storage combi ???

 

[Mbear]

you have check valves.....

Ye true, I think it would need 2 x 2ports though for hw supplies and obviously 2 x 2ports for heating and cyl

 

[Mbear]

easier to just fit a b igger combi or storage combi ???

There's nowt wrong with my current combi at all plus I would do no such thing as fit a crappy hiflow in my house lol. I get enough problems with them at work hehe

 

[dancinplumba]

would never ever suggest a worcester lol...

 

[Billy Bob Bob]

There's nowt wrong with my current combi at all plus I would do no such thing as fit a crappy hiflow in my house lol. I get enough problems with them at work hehe

i think you have been on here long enough now mbear to join the plumbers arms and gsr forum,and you fit BAXI,s and hate Worcesters thats great in my book LOL

 

[dancinplumba]

i hate em too gas man....