A.O. Smith DB/DW-720-1810 warranty Pre-Trouble-Shooting

Page 35

1.Remove main burners from unit.

2.Check that burner venturi and ports are free of foreign matter.

3.Clean burners with bristle brush and/or vacuum cleaner 3/4" DO NOT distort burner ports or pilot location.

4.Reinstall burners in unit. Making sure front and rear of burners are installed correctly in burner support brackets.

Also check for good flow of combustion and ventilating air to the unit. Maintain a clear area around the boiler at all times.

After placing the boiler in operation check the ignition system safety shutoff devices for proper operation. To accomplish this with the main burners operating, close the pilot adjusting valve on the left side of the manifold. Within four seconds the main burners and pilot should extinguish and the spark igniter on the pilot assembly should begin sparking. If this does not occur immediately, discontinue gas supply by closing main manual shutoff and call a qualified serviceman to correct the situation. If the burners extinguish, and pilot assembly begins sparking, the system is operating correctly so discontinue electrical power, open pilot adjusting valve, and light boiler in accordance with lighting and operating instructions.

For installations above 2000 feet (600 m), refer to HIGH ALTITUDE INSTALLATIONS in the installation section.

PRE-TROUBLE-SHOOTING

Before any extensive trouble-shooting, perform the following:

Ensure that:

—Power (120 vac) is supplied to the appliance.

—System control (tank temperature control, thermostat, etc.) is calling for appliance operation (call for heat).

—Other contacts (switches) are closed (transformer relay, low water cutoff, flow switch, limit controls, pressure switches, etc.)

—Gas supply pressure is within the maximum and minimum operating ranges listed on the appliance rating plate/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/connectors are firmly attached to valves, modules, switches, limit controls, etc.

—There has been no damage caused by freezing, inoperative pumps, etc.

TROUBLE-SHOOTING

 

SYSTEM OPERATION

 

 

CHECKOUT SEQUENCE

CORRECT

INCORRECT

CAUSE

REMEDY

 

 

 

 

 

Set tank/system temperature

Circulating pump

Pump and burner

Temp. control

Replace.

control (thermostat) 20°F (12°C)

and burner

remain on.

(thermostat) defective.

 

below tank water temperature.

shutoff.

 

System wiring

Correct wiring.

 

 

 

incorrect

 

 

With thermal

Circulating pump

Pump wired for

Correct wiring.

 

balancer, pump

on.

continuous operation.

 

 

off delay of

Burner on.

Gas valve stuck

Correct or replace

 

approximately

 

or defective.

valve.

 

two minutes.

 

System wiring is

Correct wiring.

 

 

 

incorrect.

 

Set tank/system temperature

Circulating pump

Circulating pump

Auto reset high limit

Replace. (If problem

control (thermostat) 20°F

and burner on.

on.

control set too low.

proven to be at this

(12°C) above tank/system

 

 

 

control by applying

water temperature.

 

 

Auto reset high limit control

jumper to terminals).

 

 

 

differential too wide.

 

 

 

 

System wiring is

Correct wiring.

 

 

 

incorrect.

 

 

 

 

Manual reset high limit

Depress reset

 

 

 

switch has activated.

button.

 

 

 

Gas valve or wiring

 

 

 

 

defective.

 

 

 

Circulating pump

Power off or system

Check power supply

 

 

and burner off.

wiring is incorrect.

and wiring.

 

 

 

Temp. control

Replace.

 

 

 

(thermostat) defective.

 

 

 

Burner on.

System wiring is

Correct wiring.

 

 

 

incorrect.

 

Boiler outlet temperature

Circulating pump.

Circulating pump

Auto reset high limit control

Replace.

exceeds 210°F (98°C) hot water

 

and burner on.

defective, or set too

 

supply, 250°F (120°C) hydronic

 

 

high (max. should

 

supply.

 

 

be set at 200°F [93°C] hot

 

 

 

 

water supply, 240°F

 

 

 

 

[115°C] hydronic supply).

 

Set tank/system temperature

System maintains

 

 

 

control (thermostat) for desired

desired water

 

 

 

water temperature.

temperature.

 

 

 

35

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Contents TM Models DB/DW-720-1810 Installation Operation Maintenance Limited WarrantyForeword ContentsReplacement Parts Levelling ROUGH-IN Dimensions CapacitiesInstallation Clearances 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 LocationVent Connection Venting the BoilerDraft Hood 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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