Valve to shut off hot water output from Megaflo cylinder

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rcssmb

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Hi
I have had a Megaflo cylinder put in my airing cupboard so that we can get good pressure to the bathroom (by a G3 Gas safe man). The 22mm hot water outlet pipe splits off to 4 other pipes. Only one of these has a gate valve (one going to the en-suite shower) and this doesn't shut down completely now anyway (its the original valve - guess 15 yr old)

I am having new showers put in to take advantage of the better flow but don't have an effective way of cutting off the supply without stopping the cold input and a partial drain on the system. So my questions.....

Am I ok to put one full bore ball valve on the outlet pipe connected to the cylinder before it splits off?

If I am ok to do this I was looking at a Pegler ball valve - is this the best type of valve for the job? Given the one and only gate valve I have doesn't work I didn't really want to get a gate valve :)

I do appreciate that this doesn't give my the flexibility of shutting off the supply to different areas - I can add these on later as needed.

Thanks
 
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No.

I think you would sruggle to find anyone to say, Yes, its ok to fit an isolation valve to a pressurised hot water cylinder outlet.

Expansion also takes place in the pipe work, dont forget.

Closing the cold water inlet, would have the same effect as closing a valve on the outlet (before any other draw offs).....and that would be to shut the water off.

What did your G3 man say, when you asked him?
 
Thanks MIGEM

Unfortunately the G3 man wasn't asked the question as the issue didn't come up until after he left.

In my simple mind I have lots of valves, ie the outlet taps, they are just further away from the cylinder - I couldn't see any harm in having one a lot closer.

I did turn off the cold supply when I needed to reseat a tap washer the other day but needed to drain off quite a bit of water before the flow stopped - seemed like about quarter of the cylinder. Enough to wash every bath sink shower and even the oven before it ran out!

Than you for your input, I might ask Heatrae Sadia for their advice about outlet control
 
Put an isolation valve before the hot water tank to cut off the hot water
if there isn't one there already.
Sorted.
 
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MIGEM said:
No.

I think you would sruggle to find anyone to say, Yes, its ok to fit an isolation valve to a pressurised hot water cylinder outlet.

Expansion also takes place in the pipe work, dont forget.

Closing the cold water inlet, would have the same effect as closing a valve on the outlet (before any other draw offs).....and that would be to shut the water off.

What did your G3 man say, when you asked him?
Click to expand...

Expansion doesn't take place in the pipework, the pipework doesn't stretch. Expansion takes place in the expansion vessel or air bubble. No problem fitting isolating valves on the outlet of an unvented cylinder. The only place you shouldn't fit valves is between the cylinder and the expansion vessel.
 
swbjackson said:
MIGEM said:
No.

I think you would sruggle to find anyone to say, Yes, its ok to fit an isolation valve to a pressurised hot water cylinder outlet.

Expansion also takes place in the pipe work, dont forget.

Closing the cold water inlet, would have the same effect as closing a valve on the outlet (before any other draw offs).....and that would be to shut the water off.

What did your G3 man say, when you asked him?
Click to expand...

Expansion doesn't take place in the pipework, the pipework doesn't stretch. Expansion takes place in the expansion vessel or air bubble. No problem fitting isolating valves on the outlet of an unvented cylinder. The only place you shouldn't fit valves is between the cylinder and the expansion vessel.
Click to expand...

Agreed.
 
Thanks Schvink and swbjackson - all the safety measures are in the cylinder (expansion vessel, pressure release valves etc) so I couldn't see an issue...

'The only place you shouldn't fit valves is between the cylinder and the expansion vessel.' - my Megaflo has an internal expansion vessel so no problem there :)

Are there any recommendations as to the most suitable type of valve, one that in 5 years time will work when I need to shut it off - or have I just been unlucky with a gate valve?
 
I would prefer to use a lever valve to be fair. Much more reliable. :cool:
 
After the initial worrying reply I emailed Megaflo support - reply pasted below

Good Morning,

There wouldn't be any issues with putting a full bore lever valve after the hot outlet as this would be no different form having a hot tap shut off. Just make sure that when you are changing your taps that the cylinder isn't being heated up. Once you've completed the refurbishment of the new taps then leave them open and then open up the gate valve to make sure that there is good flow to these taps.
Don't put the gate valve directly on the outlet, try and have this at least 500mm away from the outlet, if possible.

Kind Regards


HSH Technical
 
Excellent result! Best of luck with it all. Be sure to up date us on how you got on.
 
rcssmb said:
After the initial worrying reply I emailed Megaflo support - reply pasted below

Just make sure that when you are changing your taps that the cylinder isn't being heated up.
Don't put the gate valve directly on the outlet, try and have this at least 500mm away from the outlet, if possible.

HSH Technical
Click to expand...

swbjackson, Thanks for your comment. Im aware copper tube doesnt stretch, but expanding water water will creep into the pipework. That was my point and perhaps not clear, and more of an err on caution, for the OP.
I didnt give any measurements, as I considered the OP would have his G3 guy to install the valve appropriately.
Ta
 
Schvink said:
Excellent result! Best of luck with it all. Be sure to up date us on how you got on.
Click to expand...

Thanks guys, lovely pegler ball valve installed and confirmed working :D

Even treated myself to a new pipe cutter and realised how poor my old one was.

Bring on the other jobs now!
 
D

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