A.O. Smith BTN 120 THRU 400/A Series Venting System, Remote Storage Tank Temperature Control

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When the heater is operating at full capacity, or full gas input, it should consume 1 cu. ft. of gas in time indicated on Table 9.

VENTING SYSTEM

Examine the venting system every six months for obstructions and/or deterioration of the vent piping.

Remove all soot or other obstructions from chimney which will retard free draft.

problem persists, chlorination of the heater and replacement of the factory installed magnesium anodes with aluminum anodes may correct the condition.

Occasionally water softener companies recommend removal of heater anodes for odor reasons.

VENTING SYSTEM CAUTION

Unauthorized removal of the anode(s) will void the warranty. For further information contact your dealer.

REMOTE STORAGE TANK

TEMPERATURE CONTROL

The water temperature in the remote storage tank (if used) is controlled by the storage tank temperature control. The sensing element is mounted in the hot water storage tank, see page 13.

A change in water temperature in the storage tank lower than the tank temperature control setting will cause the sensor to activate the circulating pump. The pump then circulates the water through the heater where the thermostat senses the drop in water temperature and activates main burner operation of the appliance. If the storage tank temperature control is out of calibration, replace with new control.

REMOTE STORAGE TANK WARNING

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

RELIEF VALVE

At least once a year, the temperature and pressure relief valve should be checked 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.

If the appliance installation includes other relief valves, such as in “remote” storage tanks etc., check their relief valve operation with the same frequency.

HOT WATER ODOR WARNING

THE WATER PASSING OUT OF THE VALVE DURING THIS CHECKING OPERATION MAY BE EXTREMELY HOT. AVOID CONTACT AND DISCHARGE SAFELY TO PREVENT WATER DAMAGE.

If the temperature and pressure relief valve on the heater discharges periodically or continuously, a problem exists. This may be due to unusually high water temperatures or pressures in the system, or to a faulty relief valve. Contact your dealer or a qualified service technician to find the cause of the problem and to correct it. This may also be due to thermal expansion in a closed water supply system. Contact the water supplier or local plumbing inspector on how to correct this situation. DO NOT PLUG THE TEMPERATURE AND PRESSURE RELIEF VALVE.

ANODE ROD INSPECTION WARNING

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

HOT WATER ODOR

On occasion, hot water may develop a strong odor. If this occurs drain the heater completely, flush thoroughly, and refill. If the

ANODE ROD INSPECTION

The heater tank is equipped with anode rods to provide corrosion control. At least once a year the anode rods should be checked to determine if replacement is necessary. Initially the anode rods are approximately 7/8" in diameter with a 1/8" diameter steel core wire running down the center of the anode material. THE ANODES SHOULD BE REPLACED when the 1/8" diameter core wire is visible as this means that the anode material has been expended in the control of corrosion.

For models with top inlet and outlet, it is recommended that, before removing the inner cover for cleaning, inspection or removal of inner parts, you obtain two new nipple collars, part no. 74060. The nipple collars on the heater will usually be damaged when removed. New pipe collars will insure that the seal is such as to prevent leakage of flue products when properly installed.

NOTE: Anode rod inspection may need to be made more frequently in areas subject to acid rain that obtains their water supply from surface water as the low pH will accelerate anode activity.

CAUTION: Close cold water inlet valve serving heater and open nearby hot water faucet to relieve the pressure in the heater before attempting to remove anode(s) for inspection.

FLUSHING

1.Turn off the heater electrical disconnect switch.

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.

DRAINING

The 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 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.

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Contents INSTALLATION OPERATION MAINTENANCE LIMITED WARRANTY MODELS BTN 120 THRU 400/A SeriesCOMMERCIAL GAS, GLASS-LINED, TANK-TYPE WATER HEATER FRONT VIEW ROUGH-IN-DIMENSIONSTABLE 1. ROUGH-IN-DIMENSIONS TABLE 3. GASAND ELECTRICAL CHARACTERISTICSFOREWORD TABLE OF CONTENTSCHEMICAL VAPOR CORROSION GENERAL SAFETY INFORMATIONPRECAUTIONS GROUNDING INSTRUCTIONSELECTRONIC IGNITION CONTROL FEATURESHIGH ALTITUDE INSTALLATIONS HIGH LIMIT SWITCHLOCATING THE HEATER CIRCULATING PUMPDISHWASHING MACHINE REQUIREMENT UNCRATINGAIR REQUIREMENTS LEVELINGCLEARANCES HARD WATERCONFINED SPACE VENTINGMULTIPLE HEATER MANIFOLD UNCONFINED SPACETYPE B GAS VENT Multiple Gas Fired Tank-Type Heaters TABLE 6. TECHNICAL DATA VENTINGTABLE 6. TECHNICAL DATA VENTING Continued RELIEF VALVE WATER LINE CONNECTIONSWATER POTABLE HEATING AND SPACE HEATING See pages THERMOMETERS Not SuppliedDANGER INSTALLATION DIAGRAMS-TOP INLET/OUTLET USAGEGENERAL CODE RESTRICTIONSTEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE CONTROL VERTICAL STORAGE TANK AND FORCED CIRCULATIONHORIZONTAL STORAGE TANK AND FORCED CIRCULATION TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USEWITH RECIRCULATION OF SANITIZING LOOP TWO TEMPERATURE - ONE HEATER HIGH TEMPERATURE STORAGEINSTALLATION DIAGRAMS-SIDE INLET/OUTLET USAGE TWO TEMPERATURE - TWO HEATERS, ONE PRE-HEATER/ONE - BOOSTER HEATERWITH OR WITHOUT BUILDING RECIRCULATION HEATER WITH MIXING VALVE AND RECIRCULATED SANITIZING LOOP ONE OR TWO TEMPERATURE - ONE HEATERS,HIGH TEMPERATURESTORAGE WITH OR WITHOUT RECIRCULATION HEATER WITH OR WITHOUT MIXING VALVETWO PRE-HEATERS WITH BOOSTER HEATER TWO TEMPERATURE - TWO PRE-HEATERS WITH MIXING VALVE OR BOOSTERHEATER WITH OR WITHOUT BUILING RECIRCULATION TWO PRE-HEATERS WITH MIXING VALVEHORIZONTAL STORAGE TANK MEDIUM TEMPERATURE - ONE HEATER WITH AUXILIARY STORAGE TANK FORCEDCIRCULATION WITH OR WITHOUT BUILDING RECIRCULATION VERTICAL STORAGE TANKFOUR UNIT MANIFOLD KIT MANIFOLD KITSTWO UNIT MANIFOLD KIT THREE UNIT MANIFOLD KITFIGURE 9 - SINGLE UNIT WIRING DIAGRAM BTN-120 THROUGH 400A HEATER WIRINGCUBIC FEET PER HOUR GAS PIPINGGAS PRESSURE REGULATOR TABLE 7 - GAS SUPPLY LINE SIZES IN INCHES MAXIMUM CAPACITY OF PIPE IN1 CU. FT. OF GAS AT FULL CAPACITY OPERATIONMANIFOLD GAS PRESSURE IN INCHES OF WATER COLUMN ALL MODELS APPROXIMATE TIME REQUIRED TO CONSUMESEQUENCE OF OPERATION FOR YOUR SAFETY READ BEFORE OPERATING LIGHTING AND OPERATION INSTRUCTIONSOPERATING INSTRUCTIONS WATER TEMPERATURE CONTROL PREVENTIVE MAINTENANCECHECK THE IGNITOR ASSEMBLY IGNITOR ASSEMBLYFIGURE 11, IGNITOR MAIN BURNERGAS VALVES CHECKING THE INPUTANODE ROD INSPECTION VENTING SYSTEMREMOTE STORAGE TANK TEMPERATURE CONTROL HOT WATER ODORDELIMING USING FLO-JUG METHOD RECOMMENDED PROCEDURE FORTANK CLEANOUT PROCEDURE DELIMING SOLVENTSELECTRICAL SERVICING SERVICESYSTEM DIAGNOSTICS IGNITION MODULE SYSTEMREPLACEMENT PARTS, SERVICE HANDBOOKS AND TRAINING AIDS SEQUENCE OF OPERATION FLOW CHARTREPLACEMENT PARTS COMPLAINT OPERATIONAL CHECKLISTSERVICEMAN REMEDYKEEPTHISWARRANTYPOSTEDADJACENTTOTHEHEATERFORFUTUREREFERENCE Model BTN Limited Warranty4. SERVICEANDREPAIREXPENSES 6. CLAIMPROCEDURE