Hot water runs out when both showers are in operation.

[dynomo]

Hello chaps,
I am trying to answer a very basic question put forward to me by a friend in need. He has a 3 bedroom property, with modern indirect water system. i.e. water tank up in the loft, and a hot water cylinder etc.
He says that when both showers are in operation, the hot water seems to run out and takes ages to re-heat. We all know this is inevitable, but what would an ideal fix be for this problem. I mean can you change the hot water cylinder to a far more efficient one, to reduce waiting times when water does run out. Or could an electric water heater be added somewhere along the system?? Im a trainee electrician by trade and am slowly learning a thing or two about plumbing, the above situation is very common in nowadays homes, but what is the ultimate solution?

Thank you in advance.

 

[JohnD]

Are they Power Showers with pumps?

Test flow speed by squirting them into a bucket.

Measure the cylinder to see how big it is

Verify that it is hot almost to the very bottom.

Verify that the availability (flow) of hot water is sufficient that the cold water does not overwhelm it in the mixer. Verify that both hot and cold are supplied from the loft tank.. Measure the loft cold storage tank and see how many pipes come out of it, and what size (there ought to be a separate 15mm pipe to each shower, and a 22mm one to the cylinder).

A modern boiler should heat a modern cylinder in 20 minutes from cold. If it has an immersion heater too, this will get the top bit hot a bit quicker but has a lot less power than the boiler can provide.

 

[dynomo]

if anyone, im happy you've come to the rescue mr JohnD

Im sure the chap has 2 mixer showers. The problem doesn't link just to the showers, just generally there is a tendency for the hot water to run out from time to time. He has asked me if there is a cheap method to rectify this. I will carry out the stated when I next visit his place for sure.

But, if it turns out that everything is normal, i.e. cylinder hot to the very bottom, what would you suggest? Would you consider changing the cyliner or even the boiler, or would you add on an additional device whatever it might be to aid the boiler in supplying constant hot water?

Cheers John

 

[JohnD]

You're very kind.

But, if it turns out that everything is normal, i.e. cylinder hot to the very bottom, what would you suggest?

Bigger cylinder.

But when you come back with dimensions, capacities, flow rates and pipes, the plumber guys will doubtless have seen dozens with the same problem.

I suppose there is a chance the 3-way valve or whatever is not correctly giving the boiler priority to hot water, or it might be worn out.

Check that the boiler to cylinder flow is pumped, not gravity. Post some pics of the pump and pipe arrangements and cylinder if you can.

 

[dynomo]

cool buddy

will get all the details and let you know.
The following is a setup in a relatives house, he has a 5 bedroom, 3 storey property with 3 bathrooms, jacuzzi room etc etc and never seems to run out of hot water. Well occasionaly, it will run out, but when he is aware there is a high demand for hot water, he'll run up and switch on this baby. The water doesn't run out once done. What is all this?

 

[JohnD]

Pressurised Water Reactor (very popular round Gosport)

 

[dynomo]

can't seem to find these babies when doing a google search on 'pressurised water reactors'. Would like to read a little more about them and learn how they work.

Is there an alternate name for this system?
Oh and last but not least, can you explain the difference in a standard hot water cylinder and an immersion tank? Is that a hot water cylinder in the picture or an immersion tank? sorry for sounding so clueless, truth is, I want to learn!!!

 

[gas4you]

Big one is an un-vented mains pressure hot water cylinder, little one is expansion vessel for it

 

[dynomo]

cheers geeez
anyone on the diff between a hot water cylinder and immersion tank?

 

[JohnD]

PWR was a joke

Gosport has a submarine base. Nuclear submarines use PWRs.

I think the picture is of a pressurised hot water store.

 

[dynomo]

PWR was a joke

Gosport has a submarine base. Nuclear submarines use PWRs.

I think the picture is of a pressurised hot water store.

ooops
go on laugh all you want, i dont mind!!

 

[gas4you]

cheers geeez
anyone on the diff between a hot water cylinder and immersion tank?

None usually