A.O. Smith BTH 300A, BTH 400A Noisy Burner Operation, GAS Fails to Shut OFF, Replacement Parts

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NOTE: Always turn off and disconnect main supply wiring before servicing the unit.

4.Check connecting wire to the flame sensor. Verify that the flame sensor has not been damaged in any way.

5.Verify that the air supply is adequate. The air inlet screen or blower wheel may be restricted. Also, check the installation for proper ventilation. See AIR REQUIREMENTS.

6.Check the venting system for the correct sizing, excess or insufficient. See VENTING.

7.Check for a maximum inlet pressure of 11" Natural Gas

(2.74 kPa) W.C. and the manifold pressure as listed in Table 4: that is, for Natural Gas, 4.0" (0.996 kPa) W.C. Please note that the manifold pressure listed is the maximum value for the manifold pressure. Do not set the manifold pressure higher than the value shown for your heater in Table 4. Overfiring the heater will result in rough ignition and/or noisy operation.

8.Confirm that the air inlet screen (see Figures 7 & 8) is free of obstructions.

CAUTION

Do not reach into the burner housing or combustion chamber if the heater is still hot. Allow the heater to cool and always use gloves as the combustion chamber and the burner sleeve and housing can become very hot after operation. Overfiring is a dangerous condition that must be corrected immediately.

NOISY BURNER OPERATION

The exhaust of this unit produces some noise during ignition period. When combustion is too lean or too rich, start up noise will get worse. Check for flue gas CO2 reading, adjust gas valve manifold pressure if required to bring the flue gas CO2 to 9–9.5% level for natural gas, 10.75–11.25% for LP. This noise may be objectionable if the exhaust terminal is located too close to the opening of an occupied space. The noise may also be objectionable if the exhaust is located in the confined space between two buildings such as an alley or walkway. Since everyone's perception and tolerance for background noise varies, there is no standard recommendation. The best option when the noise is a concern is to fine-tune the air/ gas ratio of the combustion system or locate the exhaust as far away from any occupied spaces as practical.

GAS FAILS TO SHUT OFF

Check for defective gas valve or thermostat. If operation is incorrect, replace.

REPLACEMENT PARTS

Replacement parts may be ordered through A.O. Smith dealers, authorized servicers or distributors. Refer to the Yellow Pages for where to call or contact the A.O. Smith Water Products Company,

125Southeast Parkway, Franklin, TN 37068, 1-800-433-2545. When ordering parts be sure to state the quantity, part number and description of the items including the complete model and serial number as it appears on the product. Refer to the parts list for more information.

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Contents Cyclone XHE Model BTH 300A and 400A Foreword ROUGH-IN-DIMENSIONSGAS Valve Piping Table of Contents FeaturesQuick Installation Tips Horizontal Sidewall Venting Vertical Rooftop VentingHigh Limit Switch E.C.O Water Temperature Setpoint Adjustment ProcedureDishwashing Machine Requirement Required Ability Installation InstructionsCirculating Pump Insulation BlanketsUnconfined Space ClearancesHard Water Confined SpaceUS Direct Vent Canadian Direct VentUS Horizontal Vent Canadian Horizontal VentVent Pipe Termination Direct Vent Terminal InstallationDirect Venting Installation Sequence Vertical Vent Terminal InstallationInstallation of Vent System Vent Length TableBlocked Outlet Prover Switch Controls and SwitchesBlower Prover Switch Blocked Inlet Prover SwitchGAS Piping HOT Surface IgniterConnection of GAS Pipe System Connections Heater Wiring Page Sequence of Operation Self Diagnostic ControllerOperation GAS Valve LED FlashingError Codes Fault ConditionsECO Switch OPEN. See Figure Operating Instructions Adjustment Procedure Initial START-UPPrior to Start UP Required Ability Operating Instructions What to do if YOU Smell GASGeneral Information Draining Maintenance ScheduleFlushing Sediment RemovalPower Supply LED Meanings Powered Anode SystemPowered Anode Operation Drain Valve and Access PanelsInstallation Diagrams Install in Accordance with Local Codes Must be Identical Heaters Install in Accordance with Local Codes Page Manifold Kits Water is TOO HOT Burner Operational ProblemsNot Enough or no HOT Water Water Heater Makes SoundsMotor will not RUN Motor RUNS, Burner Lights Momentarily Then Locks OUTNoisy Burner Operation Replacement PartsGAS Fails to Shut OFF Model BTH Limited Warranty

BTH 300A, BTH 400A specifications

A.O. Smith has established itself as a leader in the water heating industry, offering a range of products that combine efficiency, reliability, and innovative technology. Among these products, the BTH 300A and BTH 400A models stand out for their advanced features and robust performance, catering to both residential and commercial needs.

The BTH 300A and BTH 400A are high-efficiency water heaters designed with cutting-edge condensing technology, allowing for significant energy savings compared to traditional water heating systems. These models utilize a modulating gas valve that adjusts the burner operation based on the demand for hot water. This smart system not only enhances efficiency but also ensures a consistent supply of hot water without the worry of fluctuations.

One of the standout features of the BTH series is its compact design. Both the BTH 300A and BTH 400A are engineered to fit into smaller spaces, making them ideal for properties with limited installation areas. Their lightweight construction and user-friendly installation features further simplify the process, ensuring that homeowners and professionals alike can set them up with ease.

The BTH models are equipped with advanced control systems that offer precise temperature adjustment capabilities. Users can easily customize their hot water settings to meet specific household or business requirements. This adaptability is supported by the built-in digital display, which provides real-time information about the operating status of the unit.

Safety is a key consideration in the design of the BTH 300A and BTH 400A. They feature a robust set of safety mechanisms, including temperature lockout and venting safeguards, ensuring reliable operation and peace of mind for users. A.O. Smith also understands the importance of longevity in water heaters, and these models are built with high-quality materials, making them resistant to corrosion and wear over time.

In terms of performance, both the BTH 300A and BTH 400A models deliver exceptional heating capabilities, capable of meeting high demands while maintaining efficiency. With customer satisfaction at the forefront, A.O. Smith backs these units with an extensive warranty, demonstrating their commitment to quality and long-term performance.

In summary, the A.O. Smith BTH 300A and BTH 400A water heaters exemplify the marriage of innovation and functionality. With their energy-efficient operation, customizable settings, compact design, and advanced safety features, these models are a compelling choice for those in need of reliable and effective hot water solutions.
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