On Sep 17, 1:53*pm, Josh wrote:
On Thu, 17 Sep 2009 10:06:04 -0700 (PDT), DerbyDad03





wrote:
On Sep 15, 3:08*pm, Limp Arbor wrote:
I work in a 4 story building with standard commercial toilets and
urinals. *For some reason when the valve for the spray arm is left on
in the kitchen the toilets and urinals get supplied with hot water.
Kitchen is on the 2nd floor and the warm toilets affect at a minimum
floors 1 through 3. *The building has circulator pumps in the
basement.

Could this possibly be by design?

No this is not in WV. *It is in NJ in a building less than 10 years
old.

I had a similar (and intermittent) problem in my house, but the warm
water was supplied to *all* cold fixtures, basically "reversing" what
came out of all of my faucets, showers, toilets, etc. Warm from cold
taps, cold from warm.

We finally tracked it down to the "Y" hose on the spigot outside the
garage. I have both a hot water and cold water spigot by the garage.
The cold supply is before the pressure reducer, thus at street
pressure. The hot supply, which obviously comes from the WH, is after
the pressure reducer.

If we leave the spigots open, with a hose attached and the spray
nozzle closed, the higher pressure cold will force it's way into the
hot water line, back to the WH and force HW up through the cold water
pipes.

This puzzled us for many years, since it only happened on rare
occasions. One day I noticed it happening as my son was washing his
car and a few simple tests confirmed the cause.

This is a very good examply of why vacuum breakers on hose bibbs (a
form of check valve) aren't just nuisance code, but are a good idea --
here you were just feeding your potable water through a bit of Y hose;
maybe a health issue, maybe not, but imagine the same hose sitting in
the kids' wading pool (after they've used it for whatever kids do), or
the muddy pool of much near the garden. *All it takes is a low
pressure event (within your house or from a neighbor or fire hydrant
etc), and that dirty water is sucked into your house plumbing, into
your next glass of "fresh" water.

I couldn't stand the vacuum breakers our builder installed because
they sprayed water at you every time you turned off the faucet, but
after replacing the whole hose bibb because they were crap and leaking
elsewhere, I found that the new ones work great without spraying.

Josh- Hide quoted text -

- Show quoted text -

imagine the same hose sitting in the kids' wading pool (after
they've used it for whatever kids do), or the muddy pool of mulch near
the garden.

You now, the more I thought about your comments, the more I doubt it
would be an issue in my case.

Let's start with the fact that the only time the hose could suck water
out of the pool/puddle is if the hose was open. Now, if the hose was
open and both the hot and cold water were on, then the force of cold
water would be pushing water *out* of the hose, not pushing the hot
water back into the house. If this weren't the case, I would never had
be able to fill the wading pool with warm water or for that matter,
ever get warm water out of the hose, which I do.

The only time the problem occurs in when the hose end is closed and
the cold water has no place to go but back into the house.