Jump to content
Complete France Forum

Plumbing help required please.


Bugsy

Recommended Posts

The water company have, on two occasions recently, dug up and repaired damaged pipes about a kilometre away from our house.

Since then we have a terrible problem with air in our system.

I've tried opening all the taps which does produce lots of air prior to pure water but a half-hour later, same problem.

With the high pressure in france I'm concerned its going to 'blow' the pipes off.

Is there a set procedure for a house bleed in terms of do this first, second etc.

thanks.

Link to comment
Share on other sites

[quote user="Bugsy"]The water company have, on two occasions recently, dug up and repaired damaged pipes about a kilometre away from our house.
Since then we have a terrible problem with air in our system.
I've tried opening all the taps which does produce lots of air prior to pure water but a half-hour later, same problem.
With the high pressure in france I'm concerned its going to 'blow' the pipes off.

Is there a set procedure for a house bleed in terms of do this first, second etc.

thanks.
[/quote]

First law of Hydraulics, Bugsy, is that fluids are fundamentally incompressable.

If the water main operates at say 10 Bar, then any free air will also be pressurised to Ten bar: it can at no time be at a pressure greater than the base operational pressure.

QED: if that pressure of water doesn't blow up your installation, then the same pressure of water and air can't either!

What's causing you concern is the wave front as the water compresses the air: then the water surges back; this is causing "Slugs" of water to pump out in cycles. My hot feed to the kitchen does precisely the same when I turn on the main and ballon after draining it down for the Winter.

The kitchen mixer tap leaps backwards and forwards with each surge and huge knocking sounds resonate along the hot water feed pipe! Which is circa 15 metres from ballon to kitchen sink. I've never had the brass ones to visit the Greniere and watch the copper feed pipe as yet!

This phenomenon can only be caused by trapped air still in the system: or an air leak which is somehow sucking in more air: now that's hugely unlikely, 'cos it would neccesitate ambient atmospheric air pressure being greater than the standing pressure in the water main!

The water would spray out: rather than the air sneak in!

It can be quite amazing how much air can be trapped in a mains system: and how long it takes to bleed out: it's probably trapped in a high point.

Personally, I would complain, bitterly, to your water syndicat/company, 'cos to bleed out the air will cost you a bundle in wasted, metered water.

Their Main: Their Supply: Their Problem!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...