A.O. Smith DB/DW-720-1810, User Manual

Page 1: ...the fire department Installation and service must be performed by a qualified installer service agency or the gas supplier PRINTED IN U S A 2221 0302 CAUTION TEXT PRINTED OR OUTLINED IN RED CONTAINS I...

Page 2: ...ars on the product Refer to the parts lists for more information For Technical Assistance call A O Smith Technical Information Center at 1 800 527 1953 WARNING THE INLET OUTLET WATER MANIFOLD ON YOUR...

Page 3: ...inches mm inches mm inches mm inches mm inches mm A 46 1 2 1181 52 1 5 1326 57 3 4 1467 52 7 8 1343 58 1 2 1486 64 1 2 1638 69 1 2 1765 75 1905 82 1 2 2096 B 29 5 8 752 29 5 8 752 29 5 8 752 32 3 4 8...

Page 4: ...03 1 336 1 203 1 114 1 093 1 002 954 925 859 354 LPH 22 762 15 175 12 646 11 381 9 105 8 430 7 587 6 504 6 323 5 691 5 058 4 552 4 215 4 139 3 794 3 613 3 502 3 252 1 350 000 GPH 6 709 4 473 3 727 3 3...

Page 5: ...d every water storage tank in a hot water supply system The storage tank temperature and pressure relief valve must comply with the applicable construction provisions of the Standard for Relief Valves...

Page 6: ...temperature rise at LO thermostat sensor location will continue to rise until shut off by high limit or drop causing heater to go back to full input Other system design temperatures will require rese...

Page 7: ...utoff device must be installed in the boiler outlet at the time of installation For installation locations with elevations above 2 000 feet 610 M refer to the HIGH ALTITUDE INSTALLATIONS section of th...

Page 8: ...sion must be made if the boiler is installed in confined space or a small boiler room to accommodate draft hood spillage and avoid risks described above The upper air opening called for in the AIR REQ...

Page 9: ...s outlined above return doors windows exhaust fans fireplace dampers and any other gas burning appliance to their previous conditions of use GAS CONNECTIONS WARNING THIS BOILER IS NOT INTENDED TO OPER...

Page 10: ...of 0 3 inches of water and a specific gravity of 0 60 which is approximately for natural gas LP gas has an S G of about 1 53 If the service pressure is five inches water column or less use one pipe si...

Page 11: ...u per Cubic Foot of Gas 1 000 With a cubic foot per hour demand of 3 360 and with 50 lineal feet of gas supply line table 4 shows a pipe size of 3 is required NOTE For other than 60 specific gravity a...

Page 12: ...agrams is recom mended especially for modern commercial hydronic systems VENT VALVES It is recommended that automatic loose key or screwdriver type vent valves be installed at each convector or radiat...

Page 13: ...ockwise 3 For lower flow rate turn the range adjusting screw counterclockwise Where units are installed in multiples each boiler must be individually protected by a safety flow switch CIRCULATING PUMP...

Page 14: ...st temperature which satisfies the user s hot water needs This will also provide the most energy efficient operation of the water heater and minimize scale formation SETTING THE WATER TEMPERATURE AT 1...

Page 15: ...determine if boiler will shut down or if unit will return smoothly to full input Dura Max models may also be equipped with modulation which automatically adjusts the boiler output to match the system...

Page 16: ...TRIC POWER TO BUILDING CIRCULATOR 2 MAIN FLOW SWITCH PROVES MAIN WATER FLOW BEFORE ENERGIZING SEQUENCING AND RESETTING CONTROLS 3 OUTDOOR THERMOSTAT REQUIRED IF BUILDING CONTROLS DO NOT PROVIDE AUTOMA...

Page 17: ...gle bulb outdoor sensing control will serve this requirement This precaution will prevent overheating of halls stairways or other uncontrolled areas There are occasions when outdoor temperatures are t...

Page 18: ...ence the boiler on and off in relation to the load on the system Pressure drop includes the loss through 40 12 m of pipe and normal fittings Water Category Grain Hardness per Gal Soft 1 through 7 5 No...

Page 19: ...EACH BOILER 2 BOILER PIPE LOOP See Piping Sizing Data Table 3 3 BOILER CIRCULATING PUMP See Piping Sizing Data Table 3 4 THERMOMETER 5 PRESSURE GAUGE 6 LOW WATER CUT OFF If Required By Local Code 7 SA...

Page 20: ...LENT IF ANY OF THE ORIGINAL WIRES AS SUPPLIED MUST BE REPLACED USE ONY TYPE 105 C THERMOPLASTIC OR ITS EQUIVALENT IF ANY OF THE ORIGINAL WIRES AS SUPPLIED MUST BE REPLACED BOILER CONVENTIONAL SYSTEM F...

Page 21: ...21 DURA MAX PUMP MOUNT SINGLE STAGE SCHEMATIC DIAGRAM DURA MAX SINGLE STAGE FIRING UNITED STATES MODELS WITH PUMP 120 VOLT SYSTEM CONTROLLER...

Page 22: ...22 DURA MAX PUMP MOUNT DUAL STAGE SCHEMATIC DIAGRAM DURA MAX DUAL STAGE FIRING UNITED STATES MODELS WITH PUMP 120 VOLT SYSTEM CONTROLLER...

Page 23: ...23 DURA MAX PUMP MOUNTED MODULATING SCHEMATIC DIAGRAM DURA MAX MODULATED FIRING UNITED STATES MODELS WITH PUMP 120 VOLT SYSTEM CONTROLLER...

Page 24: ...24 DURA MAX SINGLE STAGE FIRING SCHEMATIC DIAGRAM DURA MAX SINGLE STAGE FIRING UNITED STATES CANADIAN MODELS WITHOUT PUMP 120 VOLT SYSTEM CONTROLLER...

Page 25: ...25 DURA MAX DUAL STAGE FIRING SCHEMATIC DIAGRAM DURA MAX DUAL STAGE FIRING UNITED STATES CANADIAN MODELS WITHOUT PUMP 120 VOLT SYSTEM CONTROLLER...

Page 26: ...26 DURA MAX MODULATED FIRING SCHEMATIC DIAGRAM DURA MAX MODULATED FIRING UNITED STATES CANADIAN MODELS WITHOUT PUMP 120 VOLT SYSTEM CONTROLLER...

Page 27: ...or the threshold type of water treatment is recommended This will protect the dishwashers coffee urns water heaters water piping and other equipment When water softening or water treatment is not prac...

Page 28: ...ERRUPTION OR CIRCULATOR FAILURE CAUTION PUMP MUST BE RATED FOR SYSTEM OPERATING TEMPERA TURES AND PRESSURE SEE TABLE 7 FOR GUIDE TO PIPE AND PUMP SIZING SAFETY RELIEF VALVE RATING SHOULD NOT EXCEED PR...

Page 29: ...CING BOILER HOWEVER LOCAL CODES SHALL GOVERN THEIR USAGE ALL PIPING MUST BE SUPPORTED IMPORTANT THE INSTALLATION OF SAFETY FLOW SWITCHES AS SHOWN IS REQUIRED TO PROTECT THE BOILER IN CASE OF WATER SER...

Page 30: ...BE RATED FOR SYSTEM OPERATING TEMPERATURE AND PRESSURE SAFETY RELIEF VALVE RATING SHOULD NOT EXCEED PRESSURE CAPACITY OF ANY COMPONENT IN THE SYSTEM INSTALL IN ACCORDANCE WITH ALL LOCAL CODES BALL VA...

Page 31: ...T EXCEED PRESSURE CAPACITY OF ANY COMPONENT IN THE SYSTEM PIPE RELIEF VALVES TO OPEN DRAIN NOTE METRIC SIZING IS FOR COMPARISON ONLY ALL UNITS CONSTRUCTED WITH TANK FITTING MEASURED IN INCHES TANK TEM...

Page 32: ...ler to maximum setting causing a call for heat and allowing unit to run until High Limit trips 3 Reset Manual High Temperature Safety Limit Control to original temperature setting 4 Push the reset but...

Page 33: ...ERVICE TECHNICIAN TO INSPECT THE APPLIANCE AND TO REPLACE ANY PART OF THE CONTROL SYSTEM AND ANY GAS CONTROL WHICH HAS BEEN UNDER WATER 1 MAKE SURE BOILER AND SYSTEM ARE FILLED WITH WATER AND ALL AIR...

Page 34: ...NS section 1 Attach a pressure gauge or a manometer to the gauge port Check for correct manifold pressure PRESSURE SHOULD NOT EXCEED VALUE INDICATED ON RATING PLATE 2 Use this formula to clock the met...

Page 35: ...te label Voltage 24 vac is supplied by transformer Appliance is wired according to wiring diagram NOTE Cross wiring the 24 volt circuit of the relay will short the transformer All wire terminals conne...

Page 36: ...wer supply NO Is ignition cable firmly plugged into pilot assembly Securely connect cable and module and or ground wire Is ground wire firmly attached to pilot assembly and GND terminal on module YES...

Page 37: ...nto pilot assembly and module Securely connect cable Is ground wire firmly attached to pilot assembly and GND and or ground wire terminal on module YES Replace cable and or NO Are ignition cable and g...

Page 38: ...curely attached to the main firmly valve operator on the gas control and to terminals MV and MV PV on ignition module YES YES Replace main gas valve Ensure the ground wire and igntion cable are separa...

Page 39: ...ior of the inlet outlet manifold through the pressure relief valve tapping GENERAL MAINTENANCE These boilers are designed to give many years of efficient and satisfactory service when properly operate...

Page 40: ...pect to ensure tubes are free of scale and deposits If scaled remove deposits with a stiff wire brush or mechanical tube cleaner to bare metal Install new O rings and install return bends Flush system...

Page 41: ...claimed defective part to such distributor c All cost necessary or incidental for any material and or permits required for installation of the replacement 4 LIMITATIONS ON IMPLIED WARRANTIES Implied...

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Page 44: ...44 REPLACEMENT PARTS 5621 W 115TH STREET ALSIP IL 60803 PHONE 800 433 2545 FAX 800 433 2515 www hotwater com E Mail parts hotwater com...