A.O. Smith DB/DW-720-1810 warranty GAS Connections, Connecting Boiler to a Common Vent

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WARNING

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

Vent connectors serving appliances vented by natural draft shall not be connected into any portion of mechanical draft systems operating under positive pressure.

3.CONNECTING BOILER TO A COMMON VENT

Do not connect the boiler to a common vent or chimney with solid fuel burning equipment. This practice is prohibited by most local building codes as is the practice of venting gas fired equipment to the duct work of ventilation systems.

Where a separate vent connection is not available and the vent pipe from the boiler must be connected to a common vent with an oil burning furnace, the vent pipe should enter the common vent or chimney at a point ABOVE the flue pipe from the oil furnace.

UL/ULC listed doublewall type B-1 gas vents, through 24" (610

mm)diameter, can be installed in heated and unheated areas and can pass through floors, ceilings, partitions, walls and roofs, provided the required clearance is observed.

At the time of removal of an existing boiler, the following steps shall be performed with each appliance remaining connected to the common venting system. Perform these steps while the other appliances remaining connected to the common venting system are not in operation.

Seal any unused openings in the common venting system.

Visually inspect the venting system for proper size and horizontal pitch and determine there is not blockage or restriction, leakage, corrosion and other deficiencies which could cause an unsafe condition.

Insofar as is practical, close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building. Turn on clothes dryers and any appliance not connected to the common venting system. Turn on any exhaust fans, such as range hoods and bathroom exhaust fans, so they will operate at maximum speed. Close fireplace dampers.

Place in operation the appliance being inspected. Follow the lighting instructions. Adjust thermostat so appliance will operate continuously.

Test for spillage at the draft hood relief opening after five minutes of main burner operation. Use the flame of a match or candle, or smoke from a cigarette, cigar or pipe.

After it has been determined that each appliance remaining connected to the common 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.

GAS CONNECTIONS

WARNING

THIS BOILER IS NOT INTENDED TO OPERATE AT GAS SUPPLY PRESSURE OTHER THAN SHOWN ON THE RATING PLATE. EXPOSURE TO HIGHER GAS SUPPLY PRESSURE MAY CAUSE DAMAGE TO GAS VALVES WHICH CAN RESULT IN FIRE OR EXPLOSION. IF OVERPRESSURE HAS OCCURRED SUCH AS THROUGH IMPROPER TESTING OF GAS LINES OR EMERGENCY MALFUNCTION OF THE SUPPLY SYSTEM, THE GAS VALVES MUST BE CHECKED FOR SAFE OPERATION. MAKE SURE THAT THE OUTSIDE VENTS ON THE SUPPLY REGULATORS AND THE SAFETY VENT VALVES ARE PROTECTED AGAINST BLOCKAGE. THESE ARE PARTS OF THE GAS SUPPLY SYSTEM, NOT THE BOILER. VENT BLOCKAGE MAY OCCUR DURING ICE BUILD-UP OR SNOW STORMS.

WHEN LOCAL CODES REQUIRE A MAIN MANUAL SHUTOFF VALVE OUTSIDE THE BOILER JACKET, A SUITABLE MAIN MANUAL SHUTOFF VALVE MUST BE INSTALLED IN A LOCATION COMPLYING WITH THOSE CODES.

IT IS IMPORTANT TO GUARD AGAINST GAS VALVE FOULING FROM CONTAMINANTS IN THE GAS WAYS. SUCH FOULING MAY CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.

IF COPPER SUPPLY LINES ARE USED THEY MUST BE APPROVED FOR GAS SERVICE.

BEFORE ATTACHING THE GAS LINE BE SURE THAT ALL GAS PIPE IS CLEAN ON THE INSIDE.

TO TRAP ANY DIRT OR FOREIGN MATERIAL IN THE GAS SUPPLY LINE, A DIRT LEG (SOMETIMES CALLED DRIP LEG OR SEDIMENT TRAP) UPSTREAM OF THE GAS CONTROLS, MUST BE INCORPORATED IN THE PIPING. The dirt leg must be readily accessible and not subject to freezing conditions. INSTALL IN ACCORDANCE WITH RECOMMENDATIONS OF SERVING GAS SUPPLIERS. REFER TO NATIONAL FUEL GAS CODE, ANSI Z223.1 AND/OR CAN/CSA-B149.1-00.

To prevent damage, care must be taken not to apply too much torque when attaching gas supply pipe to gas valve gas inlet.

Fittings and unions in the gas line must be metal to metal type.

Apply joint compounds (pipe dope) sparingly and only to the male threads of pipe joints. Do not apply compound to the first two threads. Use compounds resistant to the action of liquefied petroleum gases.

The boiler and its individual shutoff valve must be disconnected from the gas supply piping system during any pressure testing of that system at test pressures in excess of 1/2 psi (3.5 kPa).

The boiler must be isolated from the gas supply piping system by closing its individual manual shutoff valve during any pressure testing of the gas supply piping systems at test pressures equal to or less than 1/2 psi (3.5 kPa).

The boiler and its gas connection must be leak tested before placing the boiler in operation.

Provisions for vent, bleed and gas relief lines (when applicable).

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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 Safety Relief Valves FeaturesManual Reset High Temperature Safety Limit Control Electronic Intermittent Pilot Ignition Control Safety Flow Switch Automatic Reset High Temperature Limit Control Thermal Balancer Dual Stage Models only HIGH/LOW OperatorRequired Ability Installation InstructionsLocation AIR RequirementsVenting the Boiler Draft HoodVent Connection GAS Connections Connecting Boiler to a Common VentCorrect GAS PurgingWiring Connections High Altitude InstallationsConventional Installations ExampleSystems Equipment Installation Circulating Pump Must be Properly Sized for Your Application Circulating PumpTank Temperature Control System InstallationConventional Space Heating Installation LOW Water CutoffInstallation 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 Checking and Adjusting the Input PrecautionsInternal Contaminants Pilot BurnerTROUBLE-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 Venting Maintenance General MaintenanceHeat Exchanger Preventive Maintenance Relief ValveRemoving Light Deposits of Scale Deliming SolventsMechanical Removal of Deposits Removal of AN Existing Boiler from a Common Venting SystemDURA-MAX Limited Warranty Page Page Replacement Parts