I have searched Google and looked through the manual of the unit and can
find not reason for the following...
Several months ago a friend had a new Bradford White water heater installed.
Today she noticed a slow but steady stream of water(which is hot) the width
of a "drip" started from the pressure release that is plumbed through the
wall to the outside. I looked at it and manually released the pressure
using the rocker valve on top of the unit and was able to get a "gush" of
water to flow.
The drip continues albeit a bit more slowly.
What would cause this? The unit was installed by a professional plumber
referred by a home warranty.
Anything to worry about?
Most likely nothing to worry about for the weekend. It is just leaking hot
water. Call the man back and have him replace the valve. It should not
leak and is wasting water and the power to heat it.
If steam was comming out the pipe, then it is probably running way too hot
but you should notice that at the sinks in the house when the hot water is
Pressure is too high. Could be that city Main pressure is very high
or that thermal expansion is occurring. Or (not very likely)
the brand new relief valve is faulty.
There may have been a higher-rated (over-sized) relief installed
on the old heater for that very reason. Doing so voids the
To get a decisive answer you need to actually measure the
tank pressure, not guess at a cause. You can buy a gauge
which will screw onto the hose thread on the tank drain valve.
Or...call the plumber back. If you do, don't let him BS you.
If it does turn out that Mains pressure is too high (over 80psi),
a pressure reducing valve will need to be installed (or replaced,
if there is one now) AND an expansion tank installed.
I know it sounds like a lot for a little drip, but that's what
You are just a bit off. You dont install a press red valve AND an
expansion tank if the incoming pressure is over 80psi.\\]
Those 2 parts correct 2 completely different issues.
The pressure reducing valve is almost self explainatory. It is used to
reduce the incoming city water pressure to a more manageable pressure.
The expansion tank is used when a back flow preventer is installed
somewhere in the city water system.
Measure the city water pressure at a sink or somewhere near the water
NOW, turn the water heater on/up and watch the pressure increase as
the hot water keeps heating.
Note: If a backflow preventer is installed somewhere, you will see the
If the system does NOT have a backflow preventer installed anywhere,
the pressure will just back up out into the city water system and you
wont see the pressure rise at your gauge.
If you didn't have a problem with the previous water heater, it's most
likely a bad relief valve or it has some dirt stuck in it. You can try
opening it and letting a gallon of water flow several times. If that
doesn't do it, you can either replace the valve yourself, or call back
the plumber, depending on what the warranty terms are.
Sorry, have to beg to disagree.
I fully understand the purpose of the PRV.
However, the PRV creates a closed system, just the way a backflow
device does. Yes, *some* PRV's incorporate a bypass check valve
to bleed off pressure from expansion, but they quickly clog up
or else the street pressure is too high to allow bypass.
Good practice and, frequently, inspector requirement is to
install an exp tank anytime a PRV is used.
Well, you seem to understand yet you dont seem to understand.
You might want to read this:
Lets just say you go to a customers home that has a newer water heater
and the relief valve seems to leak once or twice everyday or every
other day. You get there and the customer tells you:
She has had a plumber there 4 times to fix the leak over a month
period and its still leaking. The plumber has changed the relief valve
twice, and the PRV twice and then gave up. Yes, I got this call.
I looked at the water heater and relief valve. Nothing out of the
ordinary. I put my pressure gauge on the sink in the basement by the
water heater. It showed about 65 psi. Hmmm, nothing wrong yet.
Now I turn the water heater temp up and within less than 5 mins, my
pressure goes from 65psi to over 150 psi and starts leaking out the
The question is:
Do I replace the PRV and install an expansion tank?
Of course not. I installed and expansion tank and she was shocked that
was all it took. I later found out from the water utility that this
condo subdivision has water meters in a "pit" out in the front yard
with backflow preventers in them (as required by code).
Yes, that's what I would have done too.
The expansion pressure buildup could have been
caused by _either_ the utility backflow preventer OR
Max. unregulated pressure 80psi . . . . . . . . . . . . . . .[2903.3.1]
Expansion tank req'd if regulator not internal bypass type [2903.4]
"Water heater manufacturers and plumbing codes require the installation
of an expansion control device if a backflow preventor, **pressure
reducing valve** or check valve is installed in the domestic supply line."
Yeah, worry about the cost of heating all that
water. Easy possible fix.
2) Turn the cold water inlet valve off. Open a
hot water tap to relieve the pressure and then
shut it. Manually operate the pressure relieve
valve several times and let it snap shut. Turn
the inlet valve on and check for a leak.
3) If it continues to leak, replace the pressure
And no, the plumber probably had nothing to do
with it. If 3, it is just a failed valve.
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