should be metallic pipe or a high temperature
plastic pipe (CPVC, etc.) to insure that hot water
flow will not damage the discharge piping from
the relief valve.
In hard water areas, water treatment should be
used to reduce the introduction of minerals to the
system. Minerals in the water can collect in the
storage tank and on the immersion heating
elements causing noise on operation. Excessive
build up of minerals on the surface of the heating
elements can reduce the service life of the
elements and lead to a non-warrantable failure.
Proper operation of this electric water heater is
based on heating potable water with a hardness of
5 to 25 grains per gallon and a total dissolved
solids not exceeding 350 PPM. Consult the
manufacturer when heating potable water
exceeding these specifications. Heating of high
hardness and/or high total dissolved solids water
may require frequent cleaning of the storage tank
and heating elements to achieve proper operation.
The higher the level of dissolved solids or water
hardness, the faster the dissolved minerals in the
water will precipitate out and form scale deposits
on the heating elements and in the storage tank.
The level of scale formation is also accelerated
as stored water temperature increases. Water with
a hardness of less than 5 grains per gallon will
usually have a low pH which can be aggressive
and corrosive causing non-warrantable damage to
the storage tank, heating elements and associated
piping. Corrosion due to water chemistry
generally shows up first in the hot water system
because heated water increases the rate of
corrosive chemical reactions.
25
Water heater maintenance includes periodic tank
flushing, cleaning and removal of lime scale from
the heating elements. Where used, the water
heating system circulating pump should be oiled.
1. Turn off main power at the electrical
disconnect switch.
2. Open the drain valve. Allow water to flow
until it runs clean.
3. Close the drain valve when finished flushing.
4. Turn on the electrical disconnect switch
(after filling).
Water born impurities consist of dissolved
minerals which precipitate out of the heated water
and fine particles of soil and sand which settle out
and form a layer of sediment on the bottom of the
tank. In time, if not removed, the level of
sediment might reach the heating elements.
For convenience, sediment removal and element
lime scale removal should be performed at the
same time as follows:
Sediment and Lime Scale Removal
Sediment and lime scale accumulation on the
heating elements is a normal condition
common to all immersion type elements. Factors
which affect the amount of this formation are:
1. Amount of hot water used. As the volume
of water increases, more scale results.
2. Water temperature. As the temperature of the
water is increased, more scale is deposited on
the elements.
3. Characteristics of water supply. Regardless
of water treatment, the elements should be
examined regularly.
Avoid contact with hot
discharge water. Insure that no one is in
front of or around the relief valve
discharge line.
Make sure that the
extremely hot water manually discharged
from the relief valve will not cause bodily
injury or property damage.
CAUTION:
WATER CHEMISTRY
FLUSHING THE STORAGE TANK
SEDIMENT REMOVAL
