Shower Problems Resolved, Possibly!?

[r.rain]

Hello All

For those of you that were following my shower problems:

I had the shower engineer in today (plumber!) and he found out what was causing the cycling of the pump.

For the cycling of the pump after the hot water tap was turned off he told me to fit a non return valve in the hot water output from the HWC which was advice given on this forum. 10 out of 10

For the pulsing of the pump which would occur at anytime was because the cold water tank for the shower was lower than the cold water tank for the HWC. The difference in head was causing the hot water to be pushed through the pump down the hot water supply pipe to the shower, through the valve, up to the pump and through into the cold water tank. This is also why my overflow had been running!!! If you felt the cold water pipe it was hot!

So my plan of action is to fit the non return valve and to raise the shower cold water tank to be level with the other. If this doesn't work then non return valves will be fitted.

Will raising the cold water tank give me more pressure too and hence a better shower experience? it will need to be raised another metre or will this be negligable? if not I will just install Non return valves in the shower supply pipes.

According to the plumber I need a stronger pump to provide me with my ideal shower experience, he also stated that other body jets that were finer would provide more pressure, so pete your idea of using wire insulation may not be so bad after all! :)

Thanks for your help as usual

Cheers

Richard

[Christian McArdle]

There is actually a safety issue here. It is normal for the cold supply for the shower to be taken from the same tank as the hot water, but slightly lower, so the hot runs out first. With separate tanks, you've got the chance that the cold tank will deplete before the hot and scalding would result.

You should move both outlets to one tank (cold slightly below the hot) and link the two tanks together. You suggest it is practical to have them at the same level. Simply connecting them together with a horizontal pipe or two at low level is enough (22mm or 28mm). You can even keep the two ball valves, for additional flow.

A cheap pump will produce about 1 bar. A really good top of the range pump will only be 3 bar. Raising a tank by a metre will increase pressure by about 0.1 bar. The difference will not be great. However, you should still do it for the safety reasons stated.

Christian.

[Set Square]

I don't you recall you telling us earlier that the shower's cold feed is at a different pressure from the hot feed - that explains a lot!

It will make some difference, but it won't be dramatic - but you really need the hot and cold feeds to be at the same pressure rather than frigging about with non-return valves - which will impede the flow, anyway! Is there any reason why the cold feed can't come from the *same* tank that feeds the hot water system? That is the usual arrangement.

[Ian_m]

[r.rain]

Thanks Christian, the shower valve will actually cut out if the cold water supply fails. Someone already mentioned this to me in one of my other posts.

Cheers

Richard

[Christian McArdle]

At least, that's the hope!

I would say that the differential outlet positions is a far more reliable mechanism that anything that would be implemented in a shower valve.

If you're going to move the tank anyway, you're going to have to replumb that connection, so it might as well as be to the other tank.

Christian.

[r.rain]

I definately did in one of my other posts, it may of been burried in a reply somewhere. I thought that the pump would of taken care of this being a twin impellor doesn't that do something with equalising pressure?

Not really apart from the fact the cold water tank is pretty small that feeds the HWC and I would need to get a bigger one. The reason I used a seperate one was becuase it was there already, it used to feed an old power shower. Another issue I have is that the cold water tank feeding the HWC doesn't appear to have an overflow from it!!!! that needs sorting too.

So If I raised the cold water tank for the shower to the same level as the one that feeds the HWC the pressures would be the same and problems should go away and I also could get a slight performance increase.

Cheers

Richard

[r.rain]

I tested it and it worked.

the other tank is pretty small and I dont think would cope with feeding a 3 bar pump as well as a HWC. I would have to get a bigger one.

Cheers

Richard

[r.rain]

Ahhhh! I see sorry ignore my other posts regarding not enough capacity. The two tanks will be linked!!!!! must read things properly.

Gotcha.

I think I will do that after all.

Thanks

Richard

[Christian McArdle]

You can just link the two you have. No need to spend money (except on a couple of tank connectors and a short length of pipe.

Christian.

[Set Square]

Not when it isn't running!

That's why you get some flow from hot to cold when the valve is in a certain position - thus triggering the flow switch!