A.O. Smith TWI 35-200

Questions and Answers

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Charles RobinsonAug 20, 2025
Why is there insufficient or no hot water from my A.O. Smith Water Heater?
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  Sandra MooreAug 20, 2025
  Several factors can cause insufficient or no hot water. First, ensure the water heater is on. Second, check the supply voltage, making sure the control switch is set to I, the isolator is in the ON position, and there is power to both the isolator and the electrical connector block (230 VAC (-15%, +10%)). Also, consider if the hot water supply has been used up, and if so, reduce consumption and wait for it to reheat. Check if the controller is in OFF mode and set it to ON. Verify that the setpoint isn't too low and increase it if needed. Finally, ensure the external ON mode switch is enabled by setting "External use Enabled" to Yes.
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Anthony JohnsonAug 22, 2025
What to do if my A.O. Smith TWI 35-200 is leaking water?
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  sabrina29Aug 22, 2025
  If you notice water leakage, several areas could be the cause. Check for leaks from threaded water connections and tighten them if necessary. Inspect the condensation water discharge to ensure it's working correctly and correct it if needed. Also, look for leaks from nearby water heaters or pipe segments and trace them to their source. If the leakage is from the water heater tank itself, contact the supplier of your water heater.
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sanchezjeffreyAug 25, 2025
What to do if I smell gas from my A.O. Smith Water Heater?
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  Gina MarshallAug 25, 2025
  If you smell gas, there is likely a gas leak. Immediately close the mains gas valve, do not operate any switches, avoid open flames, and ventilate the boiler room. Then, contact your installation engineer or your local gas company.
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Denise BarrettAug 26, 2025
How to fix explosive ignition in A.O. Smith TWI 35-200 Water Heater?
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  Brittney CurtisAug 26, 2025
  Explosive ignition can occur due to several reasons. Check the gas supply pressure. Also check the CO2 value. The burner may be contaminated. Clean the burner. Inspect for air leakage between the venturi and the air connector, ensure the air connector is not damaged and is correctly connected to the venturi, tightening the clamp if necessary. Finally, check if the air inlet filter is contaminated and clean it if needed.
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Douglas BriggsAug 27, 2025
What causes CO value to be incorrect in A.O. Smith TWI 35-200 Water Heater?
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  joshuaoconnorAug 27, 2025
  An incorrect CO value can be caused by several factors. Ensure the unit is set for the correct gas type, matching the information on the rating plate and verifying the venturi restrictor has the correct diameter. Also, check for a contaminated venturi and remove any contamination from the venturi inlet. Inspect for leakage between the venturi and venturi connector, ensuring the connector is not damaged and is correctly connected, tightening the clamp if necessary. Finally, check for recirculation of flue gases, ensuring the CO2-value measured in the flue gas outlet is correct and the CO2 value measured in the air inlet is below 0.5 vol%. If necessary, reconnect the venting system and change the necessary seals.
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johnchurchAug 29, 2025
What does X54-XXXX Temperature warning mean on A.O. Smith TWI 35-200 Water Heater?
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  Kevin FloresAug 29, 2025
  The X54-XXXX temperature warning indicates that the temperature in the tank is above 90°C. To resolve this, tap off water to lower the temperature in the water heater. Check the temperature sensor for scale and replace it if necessary. Also, ensure that water is not entering the tank through the outlet and that the water heater is not being fed with water exceeding 90°C.
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Cindy ClarkAug 31, 2025
What does X57-XXXX (lock out error) Short circuit flame sensor mean on A.O. Smith Water Heater?
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  Eileen Stevens DDSAug 31, 2025
  The X57-XXXX error indicates a short circuit in the flame sensor. This can be due to an electrical connection between the flame sensor and the tank or burner. Ensure the flame sensor does not touch the tank and replace it if necessary. Also, make sure the combustion chamber is dry, the cables of the flame sensor are correctly connected, and replace the connector of the flame sensor to the correct connection if needed.
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Billy BoyerSep 1, 2025
What does XAC-XXXX (blocking error) Air proving switch error mean on A.O. Smith Water Heater?
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  Benjamin MorganSep 2, 2025
  The XAC-XXXX error indicates an issue with the air proving switch. This error means the switch is not closed when the fan is running during pre-purge. Check the hoses between the air proving switch and fan, and the air proving switch and gas control valve for damage, replace them if necessary, and reset the controller. Also, inspect the wiring between the air proving switch and the controller for damage, replace or reconnect the wires if needed, and reset the controller. Finally, check for air leakage between the venturi and air connector, replace the air connector if damaged, and ensure the hose is properly connected to the venturi, tightening the clamp if necessary.
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Zachary CameronSep 5, 2025
What does XAC-XXXX (blocking error) Fan error mean on A.O. Smith TWI 35-200 Water Heater?
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  Joshua HarrisonSep 5, 2025
  The XAC-XXXX error indicates a fan error where the switch is closed when the fan is not running. This can be caused by damaged wiring or a closed circuit between the air proving switch and the controller; replace or reconnect the wires if necessary and reset the controller. It can also be due to a defect in the air proving switch itself; replace the air proving switch if necessary and reset the controller.
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jenniferleeSep 7, 2025
What to do if the display of my A.O. Smith TWI 35-200 is off?
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  Anthony MyersSep 7, 2025
  If the display is off, it could be due to a lack of supply voltage. Ensure the isolator is in the ON position, there is power on the isolator, and there is power to the electrical connector block, with a measured voltage of 230 VAC (-15%, +10%). Also, check for defective fuse(s) and replace them if necessary.