View Single Post
  #5   Report Post  
Posted to
David Nebenzahl David Nebenzahl is offline
external usenet poster
Posts: 3,469
Default Installing new vacuum breaker on a hose bib

On 10/3/2008 10:24 AM dpb spake thus:

David Nebenzahl wrote:

By the way, after testing it I could see why these are good things
to install: after turning on the hose bib and letting the hose reel
fill up, I closed the bib, whereupon a large gush of water sprayed
out of the anti-siphon valve. Had it not been there, all that water
would have gone back inside the house plumbing, along with whatever
crap was in the hose (or in a pool the hose was thrown into, in
some cases).

How would that be if the the bib is close?

Right; duh. I should have written that *some* of that water *might* have
gone back inside the house. (A closed hose is basically a small
reservoir of water under pressure.)

Only if there's some way to build higher pressure outside than in _and_
the valve is open is there any possibility of backflow. Those are
fairly rare circumstances in general--not impossible, but certainly not
all that common.

Yep, probably true.

Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral.

- Paulo Freire