A.O. Smith BTN 120 THRU 400/A Series Preventive Maintenance, Water Temperature Control, Danger

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WATER TEMPERATURE CONTROL

WATER TEMPERATURE CONTROL

CHECKING VENTING DANGER

THIS WATER HEATER IS EQUIPPED WITH AN ADJUSTABLE THERMOSTAT TO CONTROL WATER TEMPERATURE. HOT WATER TEMPERATURES REQUIRED FOR AUTOMATIC DISHWASHER AND LAUNDRY USE CAN CAUSE SCALD BURNS RESULTING IN SERIOUS PERSONAL INJURY AND/ OR DEATH. THE TEMPERATURE AT WHICH INJURY OCCURS VARIES WITH THE PERSON'S AGE AND TIME OF EXPOSURE. THE SLOWER RESPONSE TIME OF CHILDREN, AGED OR DISABLED PERSONS INCREASES THE HAZARDS TO THEM. NEVER ALLOW SMALL CHILDREN TO USE A HOT WATER TAP, OR TO DRAW THEIR OWN BATH WATER. NEVER LEAVE A CHILD OR DISABLED PERSON UNATTENDED IN A BATHTUB OR SHOWER.

THE WATER HEATER SHOULD BE LOCATED IN AN AREA WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO SET TEMPERATURES.

SETTING THE WATER HEATER TEMPERATURE AT 120°F (49°C) WILL REDUCE THE RISK OF SCALDS. Some states or provinces require settings at specific lower temperatures.

Below you will find listed the approximate time-to-burn relationship for normal adult skin. Short repeated heating cycles caused by small hot water uses can cause temperatures at the point of use to exceed the thermostat setting by up to 20F°. If you experience this type of use, you should consider using lower temperature settings to reduce scald hazards.

Temperature

Time to Produce 2nd & 3rd

Setting

Degree Burns on Adult

180°F (82°C)

Nearly instantaneous

170°F (77°C)

Nearly instantaneous

160°F (71°C)

About 1/2 second

150°F (66°C)

About 1-1/2 seconds

140°F (60°C)

Less than 5 seconds

130°F (54°C)

About 30 seconds

120°F (49°C)

More than 5 minutes

Valves for reducing point-of-use temperature by mixing cold and hot water are available. Also available are inexpensive devices that attach to faucets to limit hot water temperatures. Contact a licensed plumber or the local plumbing authority.

The water temperature is controlled by a thermostat, fig. 2, which has two sensing elements. One sensor is located near the top of the tank and the other is near the center. The thermostat is set in the lowest position before the heater leaves the factory.

The thermostat temperature dial, fig. 2, is accessible by removing the control cover. The dial is adjustable and may be set for 1200 (49°C) to 1800F (82°C) water temperature, but 1200F (49°C) is the recommended starting point. It is suggested the dial be

placed on the lowest setting which produces an acceptable hot water supply. This will always give the most energy efficient operation. The temperature control has a 4F° fixed differential.

CHECKING VENTING

The following steps shall be followed with each appliance connected to the venting system placed in operation, while any other appliances connected to the venting system are not in operation.

1.Seal any unused openings in the venting system.

2.Inspect the venting system for proper size and horizontal pitch, as required in the National Fuel Gas Code, ANSI Z223.1or the CAN/CGA B149 Installation Codes and these instructions. Determine that there is no blockage or restriction, leakage, corrosion and other deficiencies which could cause an unsafe condition.

3.So far as is practical, close all building doors and windows and all doors between the space in which the water heater(s) connected to the venting system are located and other spaces of the building. Turn on all appliances not connected to the venting system. Turn on all exhaust fans, such as range hoods and bathroom exhausts, so they shall operate at maximum speed. Close fireplace dampers.

4.Follow the lighting instruction. Place the water heater being inspected in operation. Adjust thermostat so appliance shall operate continuously.

5.Test for spillage at the burner level after 5 minutes of main burner operation.

6.After it has been determined that each BTN connected to the venting system properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other gas burning appliance to their previous conditions of use.

7.If improper venting is observed during any of the above tests, the venting system must be corrected.

PREVENTIVE MAINTENANCE WARNING

FAILURE TO CORRECT BACK DRAFTS MAY CAUSE AIR CONTAMINATION AND UNSAFE CONDITIONS.

If the back draft cannot be corrected by the normal method or if a suitable draft cannot be obtained, a blower type flue gas exhauster must be employed to assure proper venting and correct combustion.

PREVENTIVE MAINTENANCE

CHECK THE IGNITOR ASSEMBLY

At least once a year, check the ignitor assembly, Fig. 11, and the main burner, Fig. 12, for proper operation. Refer to the following ignitor assembly and main burner sections.

IGNITOR ASSEMBLY

For access to ignitor assembly, unfasten two screws to burner cover and remove. Locate the burner with the ignitor assembly and remove screw holding burner to manifold. Slide burner out to access ignitor assembly.

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Contents MODELS BTN 120 THRU 400/A Series INSTALLATION OPERATION MAINTENANCE LIMITED WARRANTYCOMMERCIAL GAS, GLASS-LINED, TANK-TYPE WATER HEATER TABLE 1. ROUGH-IN-DIMENSIONS ROUGH-IN-DIMENSIONSTABLE 3. GASAND ELECTRICAL CHARACTERISTICS FRONT VIEWFOREWORD TABLE OF CONTENTSPRECAUTIONS GENERAL SAFETY INFORMATIONGROUNDING INSTRUCTIONS CHEMICAL VAPOR CORROSIONHIGH ALTITUDE INSTALLATIONS FEATURESHIGH LIMIT SWITCH ELECTRONIC IGNITION CONTROLDISHWASHING MACHINE REQUIREMENT CIRCULATING PUMPUNCRATING LOCATING THE HEATERCLEARANCES LEVELINGHARD WATER AIR REQUIREMENTSMULTIPLE HEATER MANIFOLD VENTINGUNCONFINED SPACE CONFINED SPACETYPE B GAS VENT Multiple Gas Fired Tank-Type Heaters TABLE 6. TECHNICAL DATA VENTINGTABLE 6. TECHNICAL DATA VENTING Continued WATER POTABLE HEATING AND SPACE HEATING See pages WATER LINE CONNECTIONSTHERMOMETERS Not Supplied RELIEF VALVEGENERAL INSTALLATION DIAGRAMS-TOP INLET/OUTLET USAGECODE RESTRICTIONS DANGERHORIZONTAL STORAGE TANK AND FORCED CIRCULATION VERTICAL STORAGE TANK AND FORCED CIRCULATIONTEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE CONTROLWITH RECIRCULATION OF SANITIZING LOOP TWO TEMPERATURE - ONE HEATER HIGH TEMPERATURE STORAGETWO TEMPERATURE - TWO HEATERS, ONE PRE-HEATER/ONE - BOOSTER HEATER INSTALLATION DIAGRAMS-SIDE INLET/OUTLET USAGEWITH OR WITHOUT BUILDING RECIRCULATION STORAGE WITH OR WITHOUT RECIRCULATION ONE OR TWO TEMPERATURE - ONE HEATERS,HIGH TEMPERATUREHEATER WITH OR WITHOUT MIXING VALVE HEATER WITH MIXING VALVE AND RECIRCULATED SANITIZING LOOPHEATER WITH OR WITHOUT BUILING RECIRCULATION TWO TEMPERATURE - TWO PRE-HEATERS WITH MIXING VALVE OR BOOSTERTWO PRE-HEATERS WITH MIXING VALVE TWO PRE-HEATERS WITH BOOSTER HEATERCIRCULATION WITH OR WITHOUT BUILDING RECIRCULATION MEDIUM TEMPERATURE - ONE HEATER WITH AUXILIARY STORAGE TANK FORCEDVERTICAL STORAGE TANK HORIZONTAL STORAGE TANKTWO UNIT MANIFOLD KIT MANIFOLD KITSTHREE UNIT MANIFOLD KIT FOUR UNIT MANIFOLD KITFIGURE 9 - SINGLE UNIT WIRING DIAGRAM BTN-120 THROUGH 400A HEATER WIRINGGAS PRESSURE REGULATOR GAS PIPINGTABLE 7 - GAS SUPPLY LINE SIZES IN INCHES MAXIMUM CAPACITY OF PIPE IN CUBIC FEET PER HOURMANIFOLD GAS PRESSURE IN INCHES OF WATER COLUMN ALL MODELS OPERATIONAPPROXIMATE TIME REQUIRED TO CONSUME 1 CU. FT. OF GAS AT FULL CAPACITYSEQUENCE OF OPERATION LIGHTING AND OPERATION INSTRUCTIONS FOR YOUR SAFETY READ BEFORE OPERATINGOPERATING INSTRUCTIONS CHECK THE IGNITOR ASSEMBLY PREVENTIVE MAINTENANCEIGNITOR ASSEMBLY WATER TEMPERATURE CONTROLGAS VALVES MAIN BURNERCHECKING THE INPUT FIGURE 11, IGNITORREMOTE STORAGE TANK TEMPERATURE CONTROL VENTING SYSTEMHOT WATER ODOR ANODE ROD INSPECTIONTANK CLEANOUT PROCEDURE RECOMMENDED PROCEDURE FORDELIMING SOLVENTS DELIMING USING FLO-JUG METHODSYSTEM DIAGNOSTICS SERVICEIGNITION MODULE SYSTEM ELECTRICAL SERVICINGSEQUENCE OF OPERATION FLOW CHART REPLACEMENT PARTS, SERVICE HANDBOOKS AND TRAINING AIDSREPLACEMENT PARTS SERVICEMAN OPERATIONAL CHECKLISTREMEDY COMPLAINT4. SERVICEANDREPAIREXPENSES Model BTN Limited Warranty6. CLAIMPROCEDURE KEEPTHISWARRANTYPOSTEDADJACENTTOTHEHEATERFORFUTUREREFERENCE