wrote in message
ups.com...


"I had a new hot water heater installed, and shortly after that, it
would discharge water."

why?
1) pressure
2) temp
3) faulty T&P

How are you going to tell if the discharge is either a faulty T&P or
due to pressure, you can't without a gauge.

How are you going to tell if the pressure is from a bad PRV, you can't
without a gauge.

You can watch the spikes on a gauge and even verify thermal expansion
is happening with a gauge.

Only an idiot would come to a conclusion without facts, at the expense
of a homeowner.
kenny b

Good questions, but a very feeble example. First of all, most home systems
don't have a point of entry where a pressure gage can be installed. Where
would you put one without taking anything apart? Obviously, one can rule
out temperature very quickly--not hard to measure or just shut off the water
heater and see if the problem recurs. Then there are times when it is just
as efficient and cost effective to substitute as it is to try and
troubleshoot. In this case, the T&P first since it is the easiest to remove
and it is also the least expensive. Maybe you can watch spikes on a gage but
in no way are you seeing what's actually happening. Have you ever recorded
large amplitude, high frequency pressure pulses with and without a gage
installed in the system? I have!! First of all, a gage does not have the
capability to respond to a transient pressure pulse; it tends to act as an
accumulator. The net result is that it attenuates and dampens out pressure
pulses in a system. Finally, you didn't address the prime topic of
discussion which is why there is a high flow for approx 10 sec after opening
a faucet. Just use some common troubleshooting sense------- If you have a
normally functioning PRV how can a defective T&P valve cause high flow out
of a faucet for 10 secs? Flow is a function of Supply Pressure and system r
esistance. The only component that is responding to the city supply pressure
is the PRV. It has to reduce that pressure to it's set point (household
pressure) and keep it at that value independent of the flow demand. The
slower the PRV responds, the bigger the variation in household pressure and
the more the variation of flow out of the faucet. In this case a gage would
certainly show a gradual reduction of pressure over a period of 10 secs
pointing to the PRV.
MLD