A.O. Smith DSE-5 THRU DSE-120 warranty Maintenance, Draining, Flushing, Sediment Removal

Always close the front access door after making a temperature adjustment. Turn on electricity.

DRAINING

The water heater must be drained if it is to be shut down and exposed to freezing temperatures. Maintenance and service procedures may also require draining the heater.

1.Turn off the electrical disconnect switch.

2.Close the supply water inlet valve to heater.

3.Attach hose to outlet opening of drain valve and direct end to drain.

4.Open a nearby hot water faucet and the heater drain valve.

5.If the heater is being drained for extended shutdown, it is suggested the drain valve be left open during this period. The hose may be removed.

•Follow FILLING instructions when restoring hot water service.

MAINTENANCE

GENERAL

Periodically the drain valve should be opened and the water allowed to run until it flows clean. This will help to prevent sediment build-up in the tank bottom.

Periodically check the temperature and pressure relief valve to ensure that it is in operating condition. Lift the lever at the top of the valve several times until the valve seats properly and operates freely.

CAUTION

THE WATER PASSING OUT OF THE VALVE DURING THIS CHECKING OPERATION MAY BE EXTREMELY HOT.

Water heater maintenance includes periodic tank flushing and cleaning, and removal of lime scale from the heating elements.

Component	Operation	Interval	Required
	Flushing	Monthly	-------------
Tank
	Sediment
	Removal	As needed	-------------
Elements	Lime Scale	As needed	UN•Lime® delimer
	Removal		and element gaskets,
			Part No.5109.

Tank flushing should be performed in accordance with the above schedule. Tank sediment removal and element lime scale removal must be performed when needed as determined by periodic inspections. Following are the instructions for performing recommended maintenance.

FLUSHING

The water heater drain valve should be opened once a month to help prevent sediment buildup on the tank bottom.

1.Turn off the electrical disconnect switch.

2.Attach hose to outlet opening of drain valve and direct end to drain.

•Open the drain valve by turning the knob to the

left (counterclockwise). Allow water to flow until it runs clean.

•If water does not flow from opened drain valve, follow instructions for sediment removal.

3.When finished flushing:

•Close heater drain valve and remove hose.

•Turn on electricity.

SEDIMENT REMOVAL

Water borne impurities consist of 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 and cause their failure.

For convenience, sediment removal and element lime scale removal should be performed at the same time as follows.

LIME SCALE REMOVAL

Lime scale accumulations 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 heated increases, more scale results.

2.Water temperature. As the temperature of water is in- creased, more scale is deposited on the elements.

3.Characteristics of water supply. Regardless of water treatment, the elements should be examined regularly.

Lime scale accumulations may cause noises to occur during operation.

It is recommended that a heating element be removed periodically for examination. If it is scaled, all of the elements should be removed and cleaned. If the tank bottom has an accumulation of sediment it should be cleaned.

Lime scale should be removed by dissolving the accumulation in UN•LIME® delimer. UN•LIME is a non-muriatic delimer, available from A.O. Smith Water Products Company, Product Service Division, 5621 W. 115th ST., Alsip, IL. 60803. Do not use muriatic or hydrochloric acid base deliming solutions to remove lime scale from the elements.

1.Turn off electrical disconnect switch.

2.Drain the heater following DRAINING instructions.

3.Open front access door.

4.Disconnect the element wiring. Try not to disturb the wiring unnecessarily and reconnection will be easier.

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