Re: Water pressure?

Aug 28, 2003 7 Replies
B


Is there a rule of thumb as to the likely static mains water pressure:


> I'm about to install an Ariston undersink heater which needs a
> pressure reducing valve if the pressure is more than 3.5 bar. The
> Thames Water site is one of those that has been expensively designed
> with not too much thought for what users might want to know.

It can vary a lot. Mine is 6 bar and I have to use such a valve on the feed to my water softener.


3.5 bar I can hold back with my finger on the tap. >5 bar I cannot
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B

Hi Tony,

You could fit the heater with the reducer valve anyway, because if the pressure is no where near to high, then the valve will act as just a safety device in times when the pressure does rise above nominal working pressure.

Fit as per instructions and you won't go wrong.

Only one other point. Does the heater have a minimum working pressure ?

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A

Good advice. The valves aren't especially expensive anyway:

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L

Wish I'd remembered to check that site before I bought the expensive and troublesome to fit, Reliance valve a couple of days ago... :-(

Pressure was 7 BAR here when measured btw, also Thames Water.

Lee

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D

Search back, I recently posted the URL of the relevant part of the OFWAT site that gives the min required pressure at the boundary stop c*ck. 7 bar springs to mind.

3.5 bar is only around 35' head just about enough to make it up to the roof tank(s) but at what flow rate. Sounds to me as if this kit is designed to be tank fed in a "normal" house rather than mains fed.
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A

Water companies are required to deliver 10 metres of head with a flow rate of 9 litres/min at the external stop tap. Not a lot is it?

.andy

To email, substitute .nospam with .gl

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I

1 bar is approx 30 foot head. 3.5 bar is approx 105 foot. 3.5 bar is very acceptable with a decent flow.
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T

THanks for all the replies: advice taken and acted on.

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