Click Image to enlarge.
Turn the hex head of the old rod counterclockwise to unscrew it. Pull
it out and screw in the new rod.
Most water heater tanks are steel
with a thin glass lining to protect
the metal from corrosion.
Since the lining eventually cracks, tanks
have a second line of defense against rust:
a long metal “anode rod” that attracts corrosive
elements in the water.When the rod
itself becomes so corroded that it can no
longer do its job, the tank soon rusts out,
leaks and needs replacement. However, if
you replace your anode rod before it fails,
about every five years, you can double the
life of your water heater.
Rods are made from magnesium, aluminum
or aluminum/zinc alloy. Aluminum
replacement rods cost about $30 each
at home centers. In most cases, the hexagonal
head of the rod is visible on the top
of the water heater. If you don’t see the
hex head, check your owner’s manual. The
rod may be under the water heater’s sheet
metal top or connected to the hot water
outlet nipple. (A few newer plastic-lined
tanks have no anode rods to replace.)
Before you get started, close the shutoff
valve, turn on the hot water at a faucet to
relieve pressure, and turn off the electricity
or gas to the heater. Open the drain
valve near the bottom of the tank and
drain out about 2 gallons of water.
CAUTION: The water is hot!
If the hex head is set below the top of
the heater, you’ll need a 1-1/16-in. socket
to reach it. If it protrudes above the top,
you can use any type of wrench. Chances
are your old anode rod will be frozen in
place by corrosion. Douse the head with a
spray lubricant such as WD-40 and give it
a few minutes to penetrate. You may also
have to slip a “cheater” pipe over the
wrench handle to increase your torque.
The weight of the water in the tank is usually
enough to keep the entire heater from
turning. But if it begins to move, have a
helper (or two) hold it in place.
When the threads break free, stop turning
and look for water around the hex
head. If you see leakage, drain the tank
further. If you don’t have enough overhead
clearance to pull the rod out of the
tank, bend it as you remove it. Then when
you buy a new rod, choose a flexible, “segmented”
version. Smear Teflon pipe
thread sealant on the threads of the new rod before you install it. Don’t use
tape, since it can reduce the
effectiveness of the rod. Before
you turn on the water and
electricity or gas, drain
another gallon out of the
tank to flush out any
remaining debris.
