A.O. Smith 1700, 3400 Flame Sensor Water Temperature Sensors, Water Temperature Limit Controls

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FLAME SENSOR

 

WATER TEMPERATURE SENSORS

Each burner is equipped with a flame sensor to detect the presence of the burner flames at high and low fire conditions. If no flame is sensed, the gas valve will close automatically. The voltage sensed by the flame sensor will also be displayed on the Burner Screen.

Figure 10.  FLAME SENSOR

WATER TEMPERATURE LIMIT CONTROLS

The “XB/XW” models incorporate an outlet water sensor having dual sensors, that are factory set at 210°F (99°C).

MAIN POWER SUPPLY SWITCH

The main power supply switch is a padlockable switch. This switch provides­ 120V from the power supply to the boiler.

This switch needs to be turned off when servicing the boiler. Note: The Enable/Disable Switch on the front of the boiler does not interrupt electrical power to the boiler.

Figure 11.  MAIN POWER SUPPLY SWITCH

Figure 12.  WATER TEMPERATURE SENSORS

Temperature sensors are threaded immersion probes. Temperature probes have embedded temperature sensors (thermistors). The boiler’s control system monitors these sensors to determine water temperature at various points in the system.

INLET AND OUTLET TEMPERATURE SENSORS

All models have two inlet and two outlet temperature sensors for each heat exchanger, factory installed to monitor the water temperature entering and leaving the boiler. The Inlet Probe is a temperature sensor only and has two leads. The Outlet probe also contains the manual reset high temperature limit switch and has four leads. The control system displays the Inlet and Outlet water temperatures sensed from these two sensors on the default Temperatures screen.

REMOTE SENSORS

All models are supplied from the factory with a remote sensor. The remote sensor is used to control system water temperature for a single boiler in a domestic hot water storage tank or in the return line from a primary/secondary hydronic heating system.

The boiler will modulate its firing rate in response to the actual system temperature and load conditions. The control system displays the temperature sensed from the remote sensor as the “Lead Lag” temperature on the default Temperatures screen.

LOW WATER CUTOFF DEVICE (LWCO)

Low water cutoff device is normally a closed switch that opens when water drops below a preset level. Each model is equipped with a factory installed LWCO. LWCO board is connected to the electronic panel, whereas the sensor probe is connected to the heat exchanger.

Figure 13.  LWCO BOARD AND PROBE

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Contents XP Boiler Table of Contents Important Definitions Safe INSTALLATION, USE and ServiceApprovals General Safety Abbreviations Used IntroductionModel Identification QualificationsDimensions and Capacity Data Operating CharacteristicsDouble Heat Exchanger Boiler Rough in Dimensions Double Ratings Electrical RequirementsFLOW, Head and Temperature Rise XB Models FLOW, Head and Temperature RiseFeatures and Components Single Heat Exchanger Boiler ComponentsDouble Heat Exchanger Boiler Components Component Description Low water cutoff board and sensor probe LwcoControl Components Main Power Supply Switch Flame Sensor Water Temperature SensorsWater Temperature Limit Controls LOW Water Cutoff Device LwcoHydronic System Boiler Installation ConsiderationsGeneral Closed Water Systems Internal ContaminantsHOT Water Boiler System General Water Line Connections Thermal ExpansionExplosion Hazard GAS ConnectionsCorrosive Materials and Contamination Sources GAS Supply Line SizingPower Supply Check Field WiringVAC Power Supply Wiring LOW Voltage Control WiringSuggested Pipe Size for Multiple GAS Appliances Natural GAS Location General RequirementsRequired Ability Replacing Existing Common Vented BoilerChemical Vapor Corrosion Installation ClearancesPanels and Covers LevelingOutdoor AIR Through ONE Opening Confined Space Outdoor AIR Through TWO OpeningsFresh AIR Openings for Confined Spaces AIR from Other Indoor Spaces Outdoor AIR Through TWO Horizontal DuctsOutdoor AIR Through TWO Vertical Ducts DuctsVenting AIR Inlet Pipe Materials Vent and AIR Pipe InstallationRequirements for Installation in Canada Direct Vent Installation Requirements Vertical Installation RequirementsHorizontal Installation Requirements Venting SupportsModels Vent KIT Numbers XB/XW Rain CAP Models Vent KIT Numbers XB/XW TEEModels Vent AIR Intake XB/XW KIT Numbers TEE Elbow Models Vent AIR Intake XB/XW KIT Numbers Rain CAP ElbowDirect VENT, Vertical Vent Horizontal Intake Termination Clearances Sidewall Power Vent Power VentTermination Clearances Sidewall Direct Vent Direct VentBELOW. Keep Clear of ALL Obstructions Termination Direct Vent Horizontal TerminationVENT/AIR Termination Locations Vertical Direct Venting Vertical TerminationPrepare ROOF/WALL Penetrations ClearancesModel Vent Diameter Vent MIN. Length Vent MAX. Length Inch Condensate Trap Condensate DisposalCondensate Neutralizer XP Models AO Smith Condensate Neutralizer KIT NumbersGAS Pressure Requirements GAS Supply ConnectionsGAS Supply Pipe Connections Check GAS Supply Inlet Pressure Pipe Sizes for Propane GASPurging GAS Line Check for GAS LeaksBoiler Start UP and Operations Filling and Purging of Heating Boiler InstallationFilling HOT Water Supply Boiler Installation Manifold Pressure ConnectionsINSPECT/FILL Condensate System Freeze Protection Hydronic Heating InstallationCHECK/CONTROL Water Hardness Water Hardness Medium 0-12 Grains PER Gallon XW ModelLighting and Operating Instructions Adjustment Setting of the Test ModeHigh Fire Rate Overview Control SystemBurner Control System Burner Control Operation SpecificationsCommunications and Displays General Operational Sequence Lead LAG LL Master General Operation Lead LAGDomestic HOT Water Definitions FeaturesLocal Operator Interface Display System Mounting the S7999B OI Display and Power Supply Installation Instructions S7999B OI DisplayQuick Setup S7999B OI Display Starting UP the S7999B OI Display POWER-UP ValidationCommon OI Display page Symbols NavigationS7999B Display page Flow Configure Button Status or HomeChange Parameter Settings Configuration PasswordLogin KeyboardExample of Change Configuration Parameter VerifyHistory Button FAULT/ALARM HandlingData Comment Example of Hydronic History Control Expanded Alert Detail Operation ButtonDiagnostics Button System Configuration S7999B OI Display onlyHydronic Control ConfigurationSystem Synchronization S7999B OI Display only Troubleshooting Code Description Recommended Troubleshooting Lockout CodesReserved ILK OFF Flame Operation Faults 105 Flame detected out of sequence Adjust the LF switch while in this position Inspect the Combustion Pressure Switch to make Code Description Recommended Troubleshooting Lockout Codes Code Description Recommended Troubleshooting Lockout Codes Code Description AllowedFan Parameter Errors Code Description Steam 20mA water temperature setting was invalid Abnormal Recycle Hardware flame bias delta high Eeprom DHW Plate Heat Exchanger Errors General Maintenance Maintenance ProceduresMaintenance Schedules Inspect Boiler AreaAIR Filter BOX Burner MaintenanceBlower Compartment Condensate Removal System Venting MaintenanceHeat Exchanger Maintenance Replacement Parts Handling Ceramic Fiber MaterialsPiping Diagrams Inlet DIAStorage Tank AOS Limited Warranty Conditions and Exceptions

3400, 1700, 2000, 2600 specifications

A.O. Smith, a leader in water heating solutions, has developed a range of high-efficiency water heaters that cater to various residential and commercial needs. Among their stellar offerings are the A.O. Smith 2600, 2000, 1700, and 3400 models, each boasting impressive features, cutting-edge technologies, and excellent energy efficiency.

The A.O. Smith 2600 model is designed for those who require a robust water heating solution with a capacity to handle high-demand scenarios. It utilizes a highly efficient heating element that provides rapid heating and maintains a steady output. The built-in smart control system allows users to monitor temperature settings and track energy consumption, ensuring optimal performance.

Next in line, the A.O. Smith 2000 is perfect for households that require a reliable and efficient water heater without compromising on space. This compact model integrates advanced thermal insulation that minimizes heat loss, coupled with a powerful heating element that ensures quick heating times. Its sleek design makes it suitable for various installations while maintaining aesthetic appeal.

The A.O. Smith 1700 model caters specifically to smaller residential needs but retains features that align with higher-end models. It incorporates state-of-the-art safety features, including overheat protection and a pressure relief valve. Its lightweight structure and ease of installation stand out, making it a recommended choice for those looking for efficient heating without extensive modifications to their plumbing systems.

Lastly, the A.O. Smith 3400 is a powerhouse designed for larger commercial applications. This model offers exceptional heating capacities and includes advanced technologies such as a digital display for easy monitoring and control. The robust build is complemented by a high-performance insulation system that significantly reduces energy consumption and operating costs.

All A.O. Smith water heaters, including the 2600, 2000, 1700, and 3400 models, feature corrosion-resistant materials ensuring longevity and durability. With their commitment to quality and innovation, A.O. Smith continues to provide water heating solutions that meet modern demands while emphasizing energy efficiency and user convenience. Whether for residential or commercial use, each model represents the pinnacle of reliability and performance in water heating technology.

In conclusion, A.O. Smith has established itself as a reliable choice for water heaters, with models that cater to diverse needs without compromising on efficiency or quality.