A.O. Smith BTH 120-250(A) warranty General Information, Maintenance

WARNING

UNDER NO CIRCUMSTANCES SHOULD THE INPUT EXCEED THE RATE SHOWN ON THE HEATER RATING PLATE. OVERFIRING COULD RESULT IN DAMAGE OR SOOTING OF THE HEATER.

CATHODIC PROTECTION

CAUTION

HYDROGEN GAS CAN BE PRODUCED INAHOT WATER SYSTEM SERVED BY THIS HEATER THAT HAS NOT BEEN USED FOR A LONG PERIOD OF TIME (GENERALLY TWO WEEKS OR MORE). HYDROGEN GAS IS EXTREMELY FLAMMABLE. To reduce the risk of injury under these conditions, it is recommended that a hot water faucet be opened for several minutes before using any electrical appliance connected to the hot water system. If hydrogen is present, there will probably be an unusual sound such as air escaping through the pipe as the water begins to flow. There should be no smoking or open flame near the faucet at the time it is open.

PRECAUTIONS

IF THE UNIT IS EXPOSED TO THE FOLLOWING, DO NOT OPERATE HEATER

UNTIL ALL CORRECTIVE STEPS HAVE BEEN MADE BY A QUALIFIED SERVICEMAN.

1.FLOODING TO OR ABOVE THE LEVEL OF THE BURNER OR CONTROLS

2.EXTERNAL FIRING

3.DAMAGE

4.FIRING WITHOUT WATER

5.SOOTING

NEVER OPERATE THE HEATER WITHOUT FIRST BEING CERTAIN IT IS FILLED WITH WATER AND A TEMPERATURE AND PRESSURE RELIEF VALVE IS INSTALLED IN THE RELIEF VALVE OPENING OF THE HEATER.

SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF, TURN OFF THE MANUAL GAS CONTROL VALVE TO THE APPLIANCE.

GENERAL INFORMATION

POWER BURNER

The initial start-up procedure of the unit is provided on page 18.

The sequence of operation of the unit is provided on page 15.

It is important to note that the controller has a reset button on the control box, Figure 1. The reset button is a safety device and would not normally be used.

HIGH LIMIT

The high limit (not adjustable) is factory set to cutout at 202°F (94°C). The controller must be manually reset by depressing the reset button on front of the control when water temperature drops to below 160°F (71°C).

TABLE 4	BTH 120	BTH 150	BTH 120,
GAS SUPPLY SPECIFICATIONS	& 250	& 199	150 & 199
	Natural Gas	Natural Gas	L.P. Gas
Max. Gas Supply Pressure W.C.	12.0	12.0	14.0
	(3 kPa)	(3 kPa)	(3.45 kPa)
Nominal Gas Supply Press. W.C	7.0	7.0	11.0
	(1.74 kPa)	(1.74 kPa)	(2.74 kPa)
Minimal Gas Supply Press. W.C.	5.0	4.5	11.0
	(1.25 kPa)	(1.12 kPa)	(2.74 kPa)
Manifold Press. W.C.	4.0	3.5	10.0
	(1 kPa)	(872 kPa)	(2.5 kPa)

HIGH ALTITUDE INSTALLATIONS

WARNING

BTH HEATERS ARE CERTIFIED FOR USE WITHOUT MODIFICATION FOR ALTITUDES UP TO 6500 FEET. INSTALLATIONS ABOVE 6500 FEET MAY REQUIRE REPLACEMENT OF THE BURNER ORIFICE. CALL THE TECHNICAL CENTER @ (800) 527-1953 FOR REQUIREMENTS.

Some gas utility companies derate their gas for altitude, making it unneccessary to install high altitude orifices. Call the local gas or utlity company to verify BTU content.

Due to the input rating reduction at high altitudes, the output rating of the appliance is also reduced and should be compensated for in the sizing of the equipment for applications.

MAINTENANCE

GENERAL

KEEP APPLIANCE AREA CLEAR AND FREE FROM COMBUSTIBLE MATERIALS, GASOLINEAND OTHER FLAMMABLE VAPORSAND LIQUIDS. (SEE WARNING ON PAGE 5, LOCATING THE HEATER).

Water heater maintenance includes periodic tank flushing and cleaning, and removal of lime scale. The unit 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 circulating pump should be oiled.

MAINTENANCE SCHEDULE

Following are the instructions for performing some of the recommended maintenance. Unit inspection and adjustment should be performed by a competent technician.

COMPONENT	OPERATION	INTERVAL	REQUIRED
Tank	Sediment	Monthly	Flushing
	Removal
Tank	Lime Scale	Semi	UN-LIME®
	Removal	Annually	Delimer
Anode	Inspect	Semi	Replace as
Rods		Annually	Required
Relief Valve	Inspect	Semi
		Annually
			SAE No. 20
Circulating	Oiling	Four Months	non-detergent
Pump (1)			motor oil
	Clean Inlet
Blower	Screen and	As Required	Soft Brush
	Blower Wheel
Vent System	Inspect	Every 3	Joints should
		Months	be sealed

(1) If furnished with oiling provision.

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