Flow rate of hot water on std cylinder!

[Christian McArdle]

However, there appears to be a difference in people's expectations of showers. Some prefer low pressure drencher showers, such as traditional wide Victorian roses, or power shower heads on "kid's bubble" mode. These require only good flow rate and can operate on very low pressures, having low resistance to flow. These can operate satisfactorily on gravity pressure systems, provided the pipework and head are OK.

Others prefer the multiple small hole spray setting, or the pulse setting. Both of these require considerable pressure to work effectively, usually more than 1 bar. These rarely work well on gravity pressure systems and usually require a pump or mains pressure.

Christian.

[Andy Hall]

What a faff just to achieve a second rate result.

[Mark]

Mains seems fine. It's 22mm most of the way from the main up to the tank. The last few metres to the shower is 15mm as with the hot but I doubt that's the problem.

Even raising or lowering of the shower head caused the temperature to drop or rise by a significant amount.

Mark

[IMM]

Usually you need a 22mm dedicated hot supply to the mixer. It is best to have a Surrey flange of the draw-off tapping, or use dedicated shower tapping off the cylinder. It is clear the mains is not right somewhere. It would take a dedicated supply back top the stoop c*ck and have a full bore s top c*ck valve.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[Christian McArdle]

Do you have high pressure? It is possible that a PRV (pressure reducing valve) just before the shower could allieviate some of the problems. Set to about 1.5 bar (or as low as you can with satisfactory performance of the shower), it will ensure that the mains doesn't fluctuate, provided that in the house pipework it remains above the set figure. It will only work if you have a high, but variable pressure.

This is more worrying, but with a low head to the hot side, I suspect that the pressure change in the hot supply upsets the venturi.

Christian.

[IMM]

Excellent performance when done properly. Read the thread. You have never seen a venturi shower in operation, you make things up.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[IMM]

All the venturi shower makers give specs in which the hot and cold must operate within. This clearly is out of spec. There are ways of getting it within spec.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[Mark]

Static pressure is just over 3 bar. There was a problem with the main stop-tap/pipework in the past. Sorting that out had no effect on the shower performance however.

If that was the case I'm surprised that turning on a cold tap (even at a low flow rate) upsets the shower temperature so much. This should have negligable effect on the hot supply.

However, saying all this, we are going to ditch the venturi shower as we are going to a combi-boiler in a few weeks.

Mark.

[Christian McArdle]

I was suggesting that there were two effects here, due to a postulating hypersenstivity of the shower mixer to pressure.

1. The hot pressure, being gravity fed would be affected by the height of the shower head.
2. The cold pressure, being mains fed with a constriction on the house feed, would be affects by other outlets in the house being turned on/off.

You may still have the problem with the cold pressure being variable.

Christian.

[Mark]

We're getting a thermostatic mixer shower so this should be better.

Regards, mark

[Andy Hall]

Where "properly" involves substantial replumbing

I have actually, but there's a lot of plumbing work to achieve the needed supplies.

it's far easier and better to eliminate all of this by using a good quality pump like a Stuart Turner and getting consistent results independent of the vagaries of the mains supply.

[IMM]

No it doesn't.

Not so. And no silly pump.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account

[Andy Hall]

Additional plumbing back to the stop tap plus rerouting is substantial and can be time consuming and expensive to do.

It is not a trivial exercise to be glossed over.

[IMM]

He has 22mm pipe most of the way from the mains. It may just require a pressure reducer before the shower to act as a regulator and/or uprating the hot pipe all, or most of the way, which will not be a long run.

_________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download

to open account