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.
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
A.O. Smith Form No. 4800, entitles Why? When? & How? 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
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
•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
•Remove drain valve from heater and insert a 3/4" x 4" drain nipple.
•Connect the clamp 1" I. D. x 3" hole to
3.Lift the
•Be sure to keep the vent just above the liquid level.
4.Place the
•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
•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
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