A.O. Smith 200M, 225M, HW-120M, 160M Features, Automatic GAS Shutoff Control, Thermal Balancer

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FEATURES

TABLE 4.

Control Device

 

Factory Setting

Field Adjustment

 

 

1950F (90.5°C) cut out temp.

 

Heater Automatic Gas Shutoff Control

Fixed

1900F (87.7°C) cut in temp.

Non-adjustable

 

 

2500F (121°C) cut out temp.

 

Heater Protector Switch

Fixed

2000F (93.3°C) cut in temp.

Non-adjustable

Tank Temperature Control

Field Supplied and Installed

Adjust to Requirements

Safety Flow Switch

See Table 1

Field Adjustable

 

 

 

 

AUTOMATIC GAS SHUTOFF CONTROL

The automatic gas shutoff control, fig. 1, is an automatic safety device which activates at a water temperature of approximately 1950F (90.5°C). This limits the water outlet temperature to a maximum of 2000F (87.7°C).

The device is wired in series with the gas valve. The control will automatically reset when the water temperature cools to approximately 190oF (87.7°C).

Should the automatic gas shutoff control activate during a heating cycle, the heater’s gas valve will close; extinguishing the main burners. The pilot burner will also be extinguished. The circulating pump will continue operating as long as the storage tank thermostat continues to “call for heat”. When the water temperature in the heater drops to 1800F (82.2°C) or below the control module will begin an ignition cycle which will relight the pilot burner and main burners. Re-ignition of the main burners will occur if the storage tank thermostat continues to call for heat. Otherwise, the normal operating cycle will resume on the thermostat’s next call for heat.

AUTOMATIC GAS SHUTOFF CONTROL

FIGURE 1

PROTECTOR SWITCH (Coil High Limit)

This heater is equipped with a manually reset protector switch, Figure 2, located under the small cover on the side of the jacket. This device provides positive shutdown of the heater in the event of heater or system malfunction. Should the surface temperature of the copper tubing heat exchanger reach 2500F (121.1°C), the protector switch will activate. The gas valve will close, and the pilot and main burners will be extinguished. To resume heater operation, the protector switch must be manually reset (remove the protector switch cover and push the reset button) after the coil surface temperature cools to less than 2000F(93.3°C).

FIGURE 2

DO NOT RESET THIS SWITCH WITHOUT PERFORMING THE SYSTEM CHECKS OUTLINED UNDER PROTECTOR SWITCH IN THE SERVICE INFORMATION SECTION. ALSO, SEE CHART ONE UNDER THE CHECKOUT SECTION. IF NECESSARY, CALL A QUALIFIED SERVICEMAN. Once the cause of the protector switch activation has been determined and corrected, it will be necessary to restart the heater following the LIGHTING AND OPERATING instructions.

THERMAL BALANCER

The thermal balancer (standard on Models HW-200M and HW-225M, optional on Models HW-120M and HW-160M) is a snap-acting single-pole thermal relay used only on Cer-Temp 80 Recovery systems. It gives immediate pump start but delay of pump shutoff for approximately 2 minutes. Residual heat in the heat exchanger is then recovered after shutdown. This improves efficiency and balances heater temperature with tank temperature at shutdown.

INTERMITTENT IGNITION CONTROL MODULE

The Honeywell S-8600 control module contain the electronic components of the system and also serve as a central wiring system for the controls mounted on the heater. The control module performs the following functions:

1.Checks for safe-start by sensing for a flame or false flame condition on start-up.

2.Generates a potential of 15,000 volts for spark ignition of the pilot burner.

3.Opens the pilot valve.

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Contents Commercial GAS Copper Heat Exchanger Water Heater Models HW-120M, 160M, 200M, 225MHeater Performance Data ROUGH-IN-DIMENSIONSForeword Table of ContentsGeneral Safety Information Grounding Instructions High Altitude InstallationsChemical Vapor Corrosion Liquid Petroleum ModelsAutomatic GAS Shutoff Control FeaturesThermal Balancer Intermittent Ignition Control ModuleSafety Flow Switch Tank Temperature ControlCirculating Pump Intermittent Ignition Control Module I.I.DDrain Valve Not Supplied Safety Flow Switch SettingsInstallation Instructions Venting Proper Vent Pipe InstallationRelief Valve Confined SpaceClosed Water System Hard WaterWater Line Connections Water Potable HeatingPiping Diagrams Page Page Correct GAS GAS ConnectionsSizing GAS Supply Line GAS Supply Pipe Sizes in InchesElectrical Information Page General OperationFilling Purging of GAS LineOperating Instructions for I.I.D. Models For Your Safety Read Before OperatingOver 170F 77C Checking and Adjusting the InputPilot and Main Burner Maintenance Service InformationD. Pilot Burner Main Burner for HW HeatersProtector Switch Continuity Test Protector SwitchThermal Balancer Schematic Diagram Inspecting the Heat Exchanger Venting SystemElectrical Service Preventive MaintenanceReplacement Parts GAS Pressure RegulatorRemoving Light Deposits Deliming SolventsHeavy Lime Deposits Deliming the HW Water HeaterSystem Operation CheckoutRemoving Silicate YES No Spark AT Pilot BurnerReplace pilot burner Replace ignition Module Spark AT Pilot Burner but Pilot will not LightMV & MV/PV? Pilot Burner Lights but Main Burner does not LightClaim Procedure Service and Repair ExpensesConditions and Exceptions Limitations on Implied Warranties

HW-120M, 225M, 200M, 160M specifications

A.O. Smith is renowned for its range of advanced water heaters, and the 160M, 200M, 225M, and HW-120M models stand out as some of the most reliable and innovative options available. These water heaters are designed to deliver exceptional performance, energy efficiency, and user-friendly features, making them ideal for various residential and commercial applications.

The A.O. Smith 160M model boasts a robust design that ensures longevity and efficiency. It has a 160-gallon capacity, providing ample hot water for households with high demand. This model incorporates insulation technology that minimizes heat loss, contributing to energy savings and reduced utility bills. Additionally, it features a durable exterior that is resistant to rust and corrosion.

The 200M model takes performance a step further with a higher capacity of 200 gallons, making it suitable for larger homes or businesses. This model is equipped with advanced components, including a high-efficiency burner and a powerful thermocouple that ensures reliable heating. The 200M also includes user-friendly controls that allow for precise temperature settings and easy operation.

Next in line is the A.O. Smith 225M, which offers an impressive 225-gallon capacity. This model is designed for heavy-duty usage and features a reinforced tank to withstand high pressure. The 225M is also equipped with state-of-the-art flame retention technology that optimizes fuel use, enhancing the overall efficiency of the unit. This ensures that customers not only get hot water when needed but also experience considerable savings on energy costs.

Finally, the HW-120M model is a compact solution that does not compromise on performance. With a capacity of 120 gallons, it is ideal for smaller households or spaces where water heating needs are moderate. The HW-120M includes features such as an LED display for easy temperature monitoring and an integrated safety system that prevents overheating.

All these models utilize advanced technologies such as electronic ignition and enhanced insulation materials, contributing to a reduction in energy consumption and maintenance needs. The combination of these features makes A.O. Smith appliances a smart choice for consumers looking for efficiency, reliability, and performance. With a strong commitment to craftsmanship and innovation, A.O. Smith continues to set the standard in water heater technology, ensuring customers enjoy reliable hot water access while promoting energy efficiency.
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