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SEDIMENT REMOVAL
Waterborne impurities consist of the particles of soil and sand which
settle out and form a layer of sediment on the bottom of the tank.
For convenience, sediment removal and lime scale removal should be
performed at the same time.
LIME SCALE REMOVAL
The amount of calcium carbonate (lime) released from water is in direct
proportion to water temperature and usage. The higher the water
temperature or water usage, the more lime deposits are dropped out of
the water. This is the lime scale which forms in pipes, heaters and on
cooking utensils.
Lime accumulation not only reduces the life of the equipment but also
reduces efficiency of the heater and increases fuel consumption.
The usage of water softening equipment greatly reduces the hardness
of the water. However, this equipment does not always remove all of the
hardness (lime). For this reason it is recommended that a regular
schedule for deliming be maintained.
The depth of lime buildup should be measured periodically. Heaters will
have about 3" (7.6 cm) of lime buildup when the level of lime has reached
the bottom of the cleanout opening or about 1" (2.5 cm) of lime buildup if
it has reached the drain valve opening. A schedule for deliming should be
set up, based on the amount of time it would take for a 1" (2.5 cm) buildup
of lime.
Example 1:
Initial inspection shows 1/2" (1.3 cm) of lime accumulation.
Therefore, the heater can be delimed once a year.
Example 2:
Initial inspection shows 2" (5 cm) of lime accumulation. Therefore,
the heater can be delimed every 3 months.
Sediment and lime scale removal may be accomplished through the
cleanout opening furnished on the heater, see Figure 25. The heater must
be drained, see DRAINING, before removing cleanout cover on tank.
FIGURE 25
To dissolve and remove the more stubborn mineral deposits, A.O. Smith
UN-LIME® Professional Delimer should be used.
A.O. Smith UN-LIME® Professional Delimer is an easy to handle
patented food grade acid formulated specifically for lime scale
removal from all types of water using equipment. Available in 1 gallon
(3.8L) (part no. 4763) and 5 gallon (19L) (part no. 4813) sizes.
Hydrochloric base acids are not recommended for use on glass-
lined tanks.
A.O. Smith Form No. 4800, entitled "Why, When and How", describes
tank cleaning methods and materials. UN-LIME and the booklet may be
obtained through your A.O. Smith dealer or distributor.
The cleanout opening is shown in Figure 25. To clean heater through
cleanout opening, proceed as follows:
1.
Turn off water inlet valve, the heater electrical disconnect switch
and open drain valve.
2.
Remove outer cover plate from lower side of heater jacket.
3.
Remove cover from cleanout opening.
4.
Remove lime, scale or sediment using care not to damage the glass-
lining.
5.
Inspect cleanout plate gasket: If new gasket is required, replace with
A.O. Smith part no. 99038.
6.
Install cleanout plate. Be sure to draw plate up tight by tightening
screws securely.
7.
Close drain valve, open water inlet line and turn on the power burner
electrical disconnect switch.
8.
Check for water leakage.
9.
Replace outer jacket cover plate.
ANODE INSPECTION AND REPLACEMENT
This water heater is equipped with multiple sacrificial anodes. Anodes
protect the glass-lined tank from corrosion by sacrificing themselves
through electrolysis. When the anode material is consumed, there is no
more protection and corrosion of the tank accelerates.
Inspection of the anode every 6 to 12 months allows you to identify a
spent anode and replace it. Replace the anode when its diameter is 3/8"
(1 cm) of an inch, or annually which ever is first. Aggressive, very hot
and softened water causes rapid consumption of the anode requiring
frequent inspections. Anodes are available from your distributor or A.O.
Smith.
REPLACEMENT PARTS
Replacement parts may be ordered through A.O. Smith dealers,
authorized servicers or distributors. Refer to the Yellow Pages for
where to call or contact A.O. Smith Water Heater Parts Fulfillment, 125
Southeast Parkway, Franklin, TN, 1-800-527-1953. When ordering parts
be sure to state the quantity, part number as it appears on the product.
Refer to the parts list for more information.
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