How to replace your own hot water heater relief valve.
Ok so you want to replace your water heater relief
First things first, this can be very dangerous and I
strongly recommend that you have it done by a
Did you read the
four reasons a relief valve leaks?
First turn the power off if electric or the gas off
Then turn off the water, it may be best to turn the
main water valve off, many times the valves by the
water heater don't hold and sometimes water feeds
back through faucets in the home.
Drain some of the water out of the water heater,
just below the relief valve. If you use the drain at
the bottom of the water heater you may find that it
will continue to leak after you try to turn it back
(another reason to have it done by a pro.)
With the power or gas off and the water off and
drained below the relief valve, remove the drain
pipe from the relief valve, if it does not have a
drain pipe on it be sure to install one on the new
relief valve. it needs to be the same size as the
outlet of the relief valve and co to about 6 inches
from the floor, without any possible way of
installing any kind of plug or cap on it.
Get your new water heater relief valve from here.
Once you have removed the drain pipe from the outlet
of the relief valve, check to be sure the water level is
below the relief valve and that no water pressure has
built up in the water heater.
||Before you remove the drain
pipe and the relief valve, you should prepare
the new one for installation, By applying pipe
dope or Teflon tape to the male threads on the
bottom of the relief valve.
Note: not all relief valves are the same, aside
from different styles like a longer body for
side mount water heaters with thick insulation.
higher BTU water heaters require a higher rated
relief valve. Water heater relief valves are
called T&P valves (temperature and Pressure
||Check the required rating for
your relief valve by checking the plate on the
water heater, you can not always go with what is
installed on the water heater because the person
that replaced the relief valve before you may
not have installed the correct relief valve.
In the image the water heater relief valve has a
copper drain pipe with an elbow pointing it
down, I unsoldered the 90 from the pipe so that
I can remove the drain pipe from the relief
valve. If you can not solder cut the pipe
leaving enough room to install a compression
coupling to replace the pipe.
||Now that you have removed the
drain pipe, again be sure the pressure did not
build up by draining off a little more water,
then put a wrench on the relief valve and turn
it counterclockwise till it unscrews all the
way. Now I am not using the correct tool to
remove the relief valve and I have the wrench on
the wrong place according to the instructions on
the relief valve. But I am careful not to damage
the new relief valve when I install it and don't
have the room to use the correct wrench on the
flat spot provided by the manufacturer.
||If you can not get the old
relief valve to turn, Stop and call a pro
Note how dirty this old relief valve is, that
sediment on the sensor may also be on the seat
of the relief valve, if so it could cause the
relief valve not to blow when needed making it
useless and very dangerous.
||Before you install the new
relief valve be sure to clean the threads on the
water heater of all sediment and debris. Go
three to four times around the threads with the
Teflon tape but keep the first few threads free
so the relief valve catches easy.
||Be very careful not to damage
the new relief valve when you tighten it up be
extra careful not to bent the outlet of the
relief valve. remember you must reinstall the
drain pipe even if the relief valve is side
mounted and already pointing down.
||Ok now that you have replaced
the relief valve and reinstalled the drain line
or installed a new drain like it is time to turn
the water back on and refill the water heater.
Do not put the power or gas back on yet. doing
so may cause problems.
||You need to get the tank 100
percent full before you turn the power on or you
may burn the top element on the water heater
I have seen this happen so many times. You turn
the water on you hear the water stop running
into the water heater and you assume it is full,
but it is not, air gets trapped in the top of
the tank. you need to run a faucet on the hot
side until you hear all of the air come out and
you get a steady flow of water before you turn
the electric or gas back on.
||When you are done check for
leaks, after the water heater has finished
heating check for leaks again, then the next day
check for leaks once more.
Note the date you installed your new relief
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