13
Lime accumulation not only reduces the life of the equipment but
a l s o r e d u c e s e f f i c i e n c y o f t h e h e a t e r a n d i n c r e a s e s f u e l
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.
Sediment and lime scale removal may be accomplished through the
cleanout opening furnished on the water heater, see FEATURES,
page 2. The heater must be drained, see DRAINING, page 12, before
removing cleanout cover on tank.
To dissolve and remove the more stubborn mineral deposits, A.O.
Smith UN•LIME
®
Professional Delimer or equivalent should be
used.
A.O. Smith UN•LIME
®
Delimer is an easy-to-handle patented food grade
acid formulated specifically for lime scale removal from all types of
water using equipment and is available in 1 gallon (Part No. 4763) and
5 gallon (Part No. 4813) sizes. Hydrochloric base acids are not
recommended for use on glass-lined tanks.
A . O . S m i t h F o r m N o . 4 8 0 0 , e n t i t l e s W h y ? W h e n ? & H o w ?
describes tank cleaning methods and materials. UN•LIME
®
and
booklet may be obtained through your A.O. Smith dealer or
distributor.
To clean heater through cleanout opening, proceed as follows:
1. Turn off water inlet valve, the oil burner electrical disconnect
switch and open drain valve and allow all water to be drained
from heater.
2. Remove outer cover plate from lower side of heater jacket.
3. Remove six (6) hex head screws securing tank cleanout plate and
remove plate.
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 oil burner
electrical disconnect switch.
8. Check for water leakage.
9. Replace outer jacket cover plate.
Flo-jug Method of Deliming
The Flo-Jug is the standard 5 gallon container for UN•LIME
®
-or- it is
available as a deliming kit with UN•LIME
®
, hose and fittings. Contact
your dealer, distributor or the A.O. Smith Water Products Company.
Figure 18 illustrates most of the following steps.
1. The heater should be prepared for deliming as described in the
"Why? When and How" booklet. The relief valve may also be delimed
at this time.
2. With the Flow-Jug upright:
•
Take off cap, remove cover under opening and install 3/4" x 4"
brass pipe nipple.
•
Drill or punch a 3/16" vent hole in handle. A stainless steel screw
is included with the Flo-Jug kit. This screw is to be installed in the
vent hole when Flo-Jug is not in use.
•
Remove drain valve from heater and insert a 3/4" x 4" drain nipple.
•
Connect the clamp 1" I. D. x 3" hole to Flo-Jug and drain nipple.
3. Lift the Flo-Jug to the POUR POSITION and permit the UN•LIME
®
to
flow into the heater as rapidly as possible.
•
Be sure to keep the vent just above the liquid level.
4. Place the Flow-Jug in the DELIME POSITION.
•
It may be necessary to place the empty jug on its carton to trap
the solution in the heater.
•
Allow the UN•LIME
®
to attack the water scale for 5 minutes.
5. Lower the Flo-Jug to the DRAIN POSITION and allow the UN•LIME
®
to flow out of the heater as rapidly as possible.
•
Observe the vent hole and elevate the jug slightly if there is a
possibility of spillage.
•
Deliming activity is indicated by foaming on the surface of the
solution.
6. Continue the deliming process:
•
Raise jug to POUR POSITION. Allow solution to flood into heater.
•
Place jug to DELIME POSITION for 5 minutes. Solution is at work in
heater.
•
Lower jug to DRAIN POSITION and allow solution to flow out.
Observe foaming.
DELIMING THE COF WATER HEATER
FIGURE 18
7. After one hour, or earlier if the deliming activity (foaming) stops,
inspect the tank interior.
•
Drain the UN•LIME® back into jug, DRAIN POSITION, and then
stand jug in DELIME POSITION.
•
Remove clamp, hose and pipe nipple from heater drain opening.
•
Observe interior through opening - a small flashlight works
well.
•
If the interior still shows water scale, the deliming process
should be continued.
•
To check UN•LIME® for continued use or reuse, place
some lime scale or white chalk into a glass with a small
