From: sbrenner@cbnewsb.cb.att.com (scott.d.brenner)
Subject: Need Help From Plumbing Gurus
Organization: AT&T
Distribution: usa
Date: Sat, 2 Jan 1993 20:39:35 GMT

I've been having some problems with the plumbing in my house
and I have a question for you plumbing wizards.

The problems started a few weeks ago when my wife and I noticed
a combination of symptoms we otherwise might have ignored.  Sink
faucets would run even if completely shut, the toilet would run
constantly, and water would leak out of the pressure relief valve
on the hot water heater.  In addition,  water would come out of
sink faucets like a fire hose for a second or two before returning 
to a normal pressure.  Then, one morning, my wife saw 5-10
gallons of water on the basement floor, apparently having come
from the pressure relief valve on the hot water heater during the
night.

I called the company that supplies water to my neighborhood and
asked them if perhaps the pressure might be too high.  They were
rather rude and simply told me that they're only responsible for
getting water to my incoming pipe; the pressure wasn't their
problem as long as I was getting water.  They mumbled something
about having to keep high pressure for the fire hydrants and told
me I should adjust my pressure-reducing valve.

When I got home, I found what I guessed to be the pressure-reducing
valve.  I turned the control screw both ways, but it didn't seem
to make a difference; things still leaked.  I finally gave in, and
called a plumber.  He told me that the reducing valve had probably
broken and he replaced it.  He told me that the pressure in my pipes
shouldn't be more than about 80 PSI and the new valve should ensure
that the pressure didn't exceed 80 pounds.  He put a gauge in the
system and I saw that the pressure was now holding steady at about
75 pounds.

The faucets and toilet haven't leaked since last weekend when the
plumber was here, and the pressure coming out of the faucets seems
more normal (no more fire hose pressure).  I have noticed, though,
that the water heater pressure relief valve lets out about 20 or 30
ounces of water a day.  This is much less than before the pressure
reducing valve was replaced, but the water heater almost never leaked
before my problems started a month ago.

Today, I saw something strange.  I checked the pressure gauge
a few times throughout the morning, and it was always at about 80
pounds.  Then, around lunchtime, I saw that the pressure gauge had 
pegged itself at about 120 PSI.  I noticed that the water heater was 
on at the time (by "on," I mean actively heating water).  I shut off
the main water supply valve to the house, which is *before* the 
pressure gauge (so the gauge still measures the pressure in the pipes,
even if the valve is closed).  I opened a faucet and let the water run
until it stopped.  The pressure dropped while the faucet was open.  
But as soon as I closed the faucet, the pressure climbed steadily, 
until the gauge pegged itself again.  Remember that the water supply
is *still* turned off and the water heater is *on*.  After the water 
heater shut off, the gauge still read about 120 PSI.  I turned the
main valve back on and opened a faucet and let the hot water run for
a minute or two.  Now the pressure dropped down to about 80 pounds and
stayed there.

I'm no plumber, but the only conclusion I can reach is that the water
heater is somehow increasing the pressure in the pipes when it is
heating water.  I don't think the water coming into the house is the
culprit, because I saw the high pressure even when the main supply
was shut off.  Also, when the water heater isn't actively heating
water, and someone has relieved the "extra" pressure by opening a 
faucet, the pressure is at a "normal" 80 pounds or so.

Am I observing a normal condition, or is this indicative of a problem?
If anyone has ever seen this behavior or has any clues or ideas that
might be helpful, I'd be very interested in hearing them.  Please
respond directly to sbrenner@attmail.com; I'll post a summary if I
get sufficient responses.

a T d H v A a N n K c S e

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Scott D. Brenner                  AT&T Consumer Communications Services
sbrenner@attmail.com                          Basking Ridge, New Jersey
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Newsgroups: misc.consumers.house