A.O. Smith Pro AOW-S400

Questions and Answers

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robbinsrichardAug 15, 2025
Why is my A.O. Smith Pro AOW-S400 Water Dispenser not producing soft water?
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  Alex JonesAug 15, 2025
  Your A.O. Smith Water Dispenser might not be producing soft water for several reasons: * The bypass valve could be in the bypass position. To fix this, place the bypass valve in the service position. * The appliance may be plumbed backward; double-check that it is plumbed correctly. * There may have been an extended power outage; reset the time of day and regenerate the unit. * The water hardness may have increased; re-test the water and re-enter a new setting number. * The unit might not be metering water. If there is no flow indicated with water usage, further inspection is needed.
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Karl BlackAug 18, 2025
What to do if my A.O. Smith Pro AOW-S400 Water Dispenser has no read-out in display?
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  Brian BrooksAug 19, 2025
  If your A.O. Smith Water Dispenser has no read-out in the display, here are a few things to check: * First, ensure the electric cord is plugged in. * Verify there is electric power at the outlet and that the outlet is not controlled by a switch. * If the power source is working, the transformer may be defective. Test with a voltmeter for 12 VAC at the control. If it's less than 10 VAC, replace the transformer. * If 12 VAC is present at the controller, the circuit board may be defective, and you should replace the controller.
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jgibsonAug 21, 2025
How to fix excess water in the brine tank of my A.O. Smith Water Dispenser?
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  Kimberly SmithAug 22, 2025
  To resolve excess water in the brine tank of your A.O. Smith Water Dispenser: * Check for a restricted, frozen, or pinched drain line. Remove any restrictions, thaw if frozen, or straighten the line. * Inspect the brine line, brine line flow control, or air check/draw tube for blockages. Clean the flow control, air check/draw tube, and brine line, removing any sediment from the brine cabinet. * Examine the injector assembly for clogs. Clean or replace the injector. If the throat is removed, replace the entire assembly.
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Courtney BakerAug 25, 2025
What to do if my A.O. Smith Pro AOW-S400 stays in regeneration?
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  cfoxAug 26, 2025
  If your A.O. Smith Water Dispenser remains in regeneration mode, consider the following: * Ensure the controller is fully pushed onto the cover plate. * The magnet disk may be defective and require replacement. * Check for any foreign objects in the main control valve and remove them. * A broken valve assembly could be the cause. If the motor is running, repair the valve assembly.
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Frederick BlackSep 7, 2025
What to do if my A.O. Smith Pro AOW-S400 Water Dispenser indicates flow when water is not being used?
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  qmarquezSep 7, 2025
  If your A.O. Smith Water Dispenser indicates flow even when water is not being used, it is likely that the household plumbing system has a leak. Repair the leak to resolve this issue.
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Mitchell AdamsSep 12, 2025
Why does my A.O. Smith Pro AOW-S400 show no flow when water is flowing?
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  gabrielcantuSep 12, 2025
  If your A.O. Smith Water Dispenser isn't indicating flow even when water is running, there are a few potential reasons: * The bypass valve might be in the bypass position. Ensure it's in the service position. * The appliance could be plumbed backward. Verify that it's plumbed correctly. * The sensor may not be receiving a signal from the magnet on the turbine. Remove the sensor from the bypass housing and test it with a magnet on either flat side. If flow is indicated, check the turbine. If no flow is indicated, replace the sensor. * The turbine might be jammed. Remove the bypass valve and clear any debris from the turbine.
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Shaun KimNov 27, 2025
How to troubleshoot controller error messages on my A.O. Smith Pro AOW-S400?
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  Brenda McbrideNov 27, 2025
  To troubleshoot controller error messages on your A.O. Smith Water Dispenser: * For a 'Home not found' error, cycle power by unplugging the transformer and plugging it back in. Ensure the controller is fully pushed onto the cover plate. * For a 'Motor error', unplug and replug all wires in the following sequence: motor, sensor, and power cord. Plug the motor in and cycle power. If the issue persists, the motor wiring or plug may be defective, or there could be a computer problem. * For a 'Home offset' error, cycle power; the controller will automatically try to reset itself. Ensure the controller is fully pushed onto the drive end cap. * For a 'Home latched' error, cycle the power to reset. This error may indicate gear teeth are not engaged, the gear is stripped, or something is j...
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Steven MillsDec 1, 2025
Why is my A.O. Smith Water Dispenser dispensing salty water?
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  Jennifer WolfeDec 1, 2025
  If your A.O. Smith Water Dispenser is dispensing salty water, it could be due to: * Low water pressure. Ensure you maintain a minimum pressure of 30 psi (2.1 bar). * A restricted drain line or flow control. Remove any restrictions. * A restricted or crimped brine line. Remove any restrictions, and replace the line if it is crimped. * An excessive amount of water in the brine cabinet. Verify the correct water level relative to the salt setting, which should be approximately 2-12 inches. Also, check the brine line and fittings for loose connections. * An intermittent pressure drop from the feed source. Consider installing a check valve on the inlet water line to the appliance (check local plumbing codes first). * The brine valve dripping water back to the brine tank. Clean the b...