A.O. Smith DB/DW-720-1810 General Maintenance, Relief Valve, Venting Maintenance, Deliming

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GENERAL MAINTENANCE

These boilers are designed to give many years of efficient and satisfactory service when properly operated and maintained. To assure continued good performance, the following recommendations are made.

The area around the unit should be kept clean and free from lint and debris. Sweeping the floor around the boiler should be done carefully. This will reduce the dust and dirt which may enter the burner and pilot air passages, causing improper combustion and sooting.

THE FLOW OF COMBUSTION AND VENTILATION AIR TO THE BOILER MUST NOT BE OBSTRUCTED.

THE BOILER AREA MUST BE KEPT CLEAR AND FREE FROM COMBUSTIBLE MATERIALS, GASOLINE AND OTHER FLAMMABLE VAPORS AND LIQUIDS.

Any safety devices including low water cutoffs used in conjunction with this boiler should receive periodic (every six months) inspection to assure proper operation. A low water cutoff device of the float type should be flushed every six months. All relief valves should be inspected and manually operated at least twice a year. More frequent inspections may be necessary depending on water conditions.

Periodic checks, at least twice a year, should be made for water and/or gas leaks.

More frequent inspections may be necessary depending on water conditions.

The boiler mounted gas and electrical controls have been designed to give both dependable service and long life. However, malfunction can occur, as with any piece of equipment. It is therefore recommended that all components be checked periodically by a qualified serviceman for proper operation.

RELIEF VALVE

The safety relief valve should be opened at least twice a year to check its working condition. This will aid in assuring proper pressure relief protection. Lift the lever at the top of the valve several times until the valve seats properly and operate freely.

DANGER

THE WATER PASSING OUT OF THE VALVE DURING CHECKING OPERATION MAY BE EXTREMELY HOT. BEFORE OPERATING RELIEF VALVE MAKE SURE DRAIN LINE IS INSTALLED TO DIRECT DISCHARGE TO A SAFE LOCATION SUCH AS AN OPEN DRAIN, TO AVOID SCALDING OR WATER DAMAGE.

WARNING

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

VENTING MAINTENANCE

Qualified servicers should follow this procedure when the boiler’s external heating surfaces and vent pipe need cleaning.

CAUTION

DO NOT USE A NYLON BRUSH OR OTHER STATIC CREATING MATERIAL TO CLEAN DUST AND CARBON DEPOSITS FROM HEATING SURFACES AND VENT.

SUCH DEPOSITS ARE FLAMMABLE AND MAY BE IGNITED BY STATIC ELECTRICITY. USE A METAL BRUSH TO MINIMIZE THE DANGER OF EXPLOSION

1.Turn off the electrical power, main manual gas shutoff and pilot valves.

•Allow boiler parts to cool before disassembly.

2.Remove the internal flue collector and vent pipe running to the chimney.

•Check parts and chimney for obstructions and clean as necessary.

3.Remove burners from boiler and other metal parts as required to clean as necessary.

•Refer to parts list supplied with this manual for disassembly aid.

4.Clean and reinstall the parts removed in steps 2 and 3.

•Be sure the vent pipe has a minimum upward pitch of one quarter inch per foot of length and is sealed as necessary.

5.Restore electrical power and gas supply to boiler.

•Check for gas leaks and proper boiler and vent operation.

HEAT EXCHANGER

PREVENTIVE MAINTENANCE

In most water supply systems some solids exist. As the water is heated, these tend to drop out depositing as scale or lime. This scale is relatively easy to remove before the unit becomes clogged.

WARNING

Lime accumulation can reduce the life of the equipment, reduce efficiency and waste fuel. Boiler failure due to lime or scale build- up voids the warranty.

See section on CIRCULATING PUMP to ensure you have selected the proper size pump for your situation.

DELIMING

The amount of calcium carbonate (lime) released from water is in direct 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, boilers and on cooking utensils.

The usage of water softening equipment greatly reduces the hardness of water. However, this equipment does not always remove all of the hardness (lime). For this reason it is recommended that a regular schedule for deliming be maintained.

Figure 29 shows typical piping arrangement for gravity deliming of lime deposits. For systems using recirculating deliming pumps contact your A. O. Smith distributor.

Lime build-up may be seen when viewing the interior of the inlet/ outlet manifold through the pressure relief valve tapping.

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Contents TM Models DB/DW-720-1810 Installation Operation Maintenance Limited WarrantyContents Replacement PartsForeword ROUGH-IN Dimensions Capacities Installation ClearancesLevelling Pressure Drop Electronic Intermittent Pilot Ignition Control FeaturesSafety Relief Valves Manual Reset High Temperature Safety Limit ControlDual Stage Models only HIGH/LOW Operator Automatic Reset High Temperature Limit ControlSafety Flow Switch Thermal BalancerAIR Requirements Installation InstructionsRequired Ability LocationVenting the Boiler Draft HoodVent Connection GAS Connections Connecting Boiler to a Common VentCorrect GAS PurgingExample High Altitude InstallationsWiring Connections Conventional InstallationsSystems Equipment Installation Circulating Pump Must be Properly Sized for Your Application Circulating PumpLOW Water Cutoff System InstallationTank Temperature Control Conventional Space Heating InstallationInstallation AS Boiler Replacement DB InstallationPage LINEAR-TEMP Space Heating Applications LINEAR-TEMP Space Heating InstallationsDuraMax Pump Performance Requirements Thermometer Pressure Gauge Safety Flow SwitchONE Boiler LINEAR-TEMP System Page Page Page Page Page Page ONE DURA-MAX Model DW Commercial Boiler with Vertical Tank Hard Water ConditionsONE DURA-MAX Model DW Commercial Boiler with Horizontal Tank NPT NPT Manifolding of Model TJV-120M & TJV-200M Tanks START-UP and Operating Instructions For Your Safety Read Before Operating Pilot Burner PrecautionsChecking and Adjusting the Input Internal ContaminantsTROUBLE-SHOOTING PRE-TROUBLE-SHOOTINGYES No Spark AT Pilot BurnerSpark AT Pilot Burner but Pilot will not Light Pilot Burner Lights but Main Burner does not Light Relief Valve General MaintenanceVenting Maintenance Heat Exchanger Preventive MaintenanceRemoval of AN Existing Boiler from a Common Venting System Deliming SolventsRemoving Light Deposits of Scale Mechanical Removal of DepositsDURA-MAX Limited Warranty Page Page Replacement Parts

DB/DW-720-1810 specifications

A.O. Smith has a longstanding reputation for quality and innovation in the water heater industry, and the DB/DW-720-1810 model exemplifies these values. This particular water heater is designed to provide reliable hot water, making it suitable for both residential and commercial applications. Its impressive features and cutting-edge technologies set it apart from conventional models.

One of the primary features of the A.O. Smith DB/DW-720-1810 is its energy efficiency. It operates using advanced insulation technologies, minimizing heat loss and promoting energy savings. This model is designed with a high-efficiency burner that substantially reduces energy consumption while maintaining optimal performance. It also complies with industry standards for energy efficiency, ensuring that users can enjoy lower utility bills without sacrificing comfort.

The DB/DW-720-1810 is equipped with a robust tank designed to hold an ample supply of hot water. With a capacity of 75 gallons, it is ideal for households with high demand, such as multi-bathroom residences or commercial establishments. This large capacity ensures that hot water is readily available for various activities, from bathing to cleaning.

User control is another notable characteristic of the A.O. Smith DB/DW-720-1810. The model features an intuitive digital display that allows users to monitor and set water temperatures easily. This interface not only enhances usability but also promotes safety, preventing scalding by allowing users to adjust the temperature to their preference.

Durability is a key consideration in the DB/DW-720-1810’s design. It is built with high-quality materials and features a corrosion-resistant tank, ensuring longevity even in challenging water conditions. This resilience is further supplemented by A.O. Smith's advanced anode rod technology, which helps battle corrosion and extends the lifespan of the water heater.

Lastly, maintenance is simplified with this model. A.O. Smith has designed the water heater for easy access to serviceable parts, making routine maintenance more convenient and less time-consuming. Coupled with warranty options that provide peace of mind, the DB/DW-720-1810 stands out as a dependable choice.

In summary, the A.O. Smith DB/DW-720-1810 combines energy efficiency, significant capacity, user-friendly controls, durability, and low maintenance needs, making it an exceptional option for those needing a reliable hot water solution.
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