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1 The valve is old and it starts to leak, They can just start to
leak in less then a year so if it is a few years old, that may be all there is
to is so it just needs to be replaced. Pictures and instructions will
follow.
2 The water is too hot. water heater relief valves will blow at
210 % f but most of the time the relief valve will blow before that temperature
because of the extra pressure caused by the water expanding. This in not to be
confused with normal thermo expansion. This is the water heater over heating and
is very dangerous. if you have noticed the hot water spitting out of the spout
or the water being very hot almost like steam you have a bad control and should
shut your water heater off and have the problem fixed. In this example the
relief valve is doing it's job, but may need to be replaced after the control
problem is fixed.
3 the pressure is too high relief valves are set at 150 psi. if
the pressure coming into your house is 150 psi or more the relief valve will
never stop leaking, Now just because your relief valve will not stop leaking
does not mean your pressure is 150 psi it may just be bad.
4 Thermo expansion When water heats it expands in most
cases with a standard 50 gallon 50,000 btu gas water heater with house pressure
of about 50 psi it will not expand enough to be a problem. but with higher
recoveries and or higher house pressure, a domestic water expansion tank
may be needed to absorb the expansion of the water.
Now
that
you
know
what
may
be
the
cause.
You
need
to
understand
that
it
can
be
dangerous
to
mess
with
a
relief
valve.
You
can
be
scalded
or
create
a
very
dangerous
situation,
possibly
resulting
in
death.
It
is
better
to
have
a
pro
do
it
for
you.
Ok so you want to replace your relief valve. First turn off the
power if electric. and turn gas to pilot setting. Then turn off the water to the
tank. then open a faucet at a lower level then the water heater if possible. If
the water stops running you are ready to replace the relief valve if not you may
have a bad mixing valve, So you will have to turn off your main water valve and
drain the water out of the lines at a sink or something. It is not necessary to
drain the whole tank just drain it to below the relief valve. |
