A.O. Smith BTPN Maintenance, Flushing, Draining, Sediment Removal, Lime Scale Removal, Component

3.The correct test instruments are:

•CO2 indicator or 02 analyzer

•CO indicator

•Stack thermometer

•Draft gauge or inclined manometer

•U-tube manometer or calibrated 0-10” and 0-35” w.c. pressure gauge

•Combination volt/ammeter.

Suggested safety device test procedures are:

A. While heater is operating, turn valve, main burner and pilot gas line manual gas cocks to the OFF position. Burner should shutdown within 3-4 seconds and lockout on flame failure, requiring reset of the flame safeguard device.

B. While heater is operating, lower the setting of each of (2) operating thermostats (one at a time). During this setting change, the burner should shutdown when the called for temperature is less than the temperature indicated on the thermometer. Restore the settings to original values and burner should restart.

Should any of the above operating test fail, replace the involved component.

MAINTENANCE

GENERAL

Water heater maintenance includes periodic tank flushing and cleaning, and removal of lime scale. The power burner should be inspected and adjusted to maintain proper combustion. Refer to the following table. A periodic inspection of the venting system should be made. Where used, the water heating system circulating pump should be oiled.

KEEP APPLIANCE AREA CLEAR AND FREE FROM COMBUSTIBLE MATERIALS, GASOLINE AND OTHER FLAMMABLE VAPORS AND LIQUIDS.

FLUSHING

1.Turn off the heater electrical disconnect switch.

•For convenience, the switch on the outside of the control compartment can be used.

2.Open the drain valve and allow water to flow until it runs clean.

3.Close the drain valve when finished flushing.

4.Turn on the heater electrical disconnect switch.

	MAINTENANCE SCHEDULE
Component	Operation	Interval	Required
	Flushing	Monthly
	Sediment
Tank	Removal	Semi-Annually
	Lime Scale		UN•LIME®
	Removal	As Required	Delimer
Relief Valve	Inspect	Semi-Annually
Power Burner			SAE No. 20
Motor(1)	Inspect	Quarterly	non-detergent
			motor oil
Power Burner			Combustion
and Ignition	Inspection	Semi-Annually	test kit &
Device(2)			test
			specifications
Main Burner	Check Flame	Annually
Flue Baffle
Pipe(3)	Cleaning	As Required	Wire Brush
Vent System
and Barometric	Inspect	Semi-Annually	Draft Gauge
Damper

(1)If furnished with oiling provisions

(2)If flange gasket is damaged, it must be repaired.

(3)COF and COBT Only.

DRAINING

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

1.Tun off the heater electrical disconnect switch.

2.Close the cold water inlet valve to heater.

3.Open a nearby hot water faucet to vent the system.

4.Open the heater drain valve.

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

• Follow FILLING instructions when restoring hot water service

SEDIMENT REMOVAL

Waterborne impurities consist of fine 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 (lime) released from water is indirect 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.

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