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    September 22, 2022 4 min read

    These are the error codes that you may encounter on the display of your Fleck 5600SXT water softener or your Fleck 5800 system. See below for a more thorough explanation of the issue, some common causes, and ways to troubleshoot and fix the issues.

    Error Code Description
    Err 0 The motor that drives the piston is stalled and cannot move. This usually occurs when the piston is jammed and motor is unable to move it.
    Err 1
    The motor is running continuously. This usually occurs when the system is first plugged in and it's not able to find the home position. It may also occur when the motor gears are stripped or the motor is not sitting properly in the motor mount.
    Err 2
    This error code occurs when the system has not been regenerated or backwashed for more than 99 days. Clear the code by manually initiating a regeneration. You should also check the programming to make sure a Day Override (DO) value has been programmed into the system.
    Err 3
    This is caused by a memory failure on the control board. You can attempt to clear this error code by performing a soft reset of the board (press and hold the leftmost button on the controller while plugging the unit into the power source, hold for a few seconds, then release)
    Err 4 This error code is usually accompanied by an exclamation point on the screen. This error code means that the the controller has detected that the piston cannot be moved to the correct position.


    Error Code "Err 0"

    This error code is generated when the motor that drives the internal components of the Fleck 5600SXT (or Fleck 5600SE) is unable to move even though it's supposed to. The motor is only engaged when the Fleck 5600SXT system is attempting do to a regeneration or a backwash. So, if you are able to clear this error code (by doing a Fleck 5600SXT soft reset or Fleck 5600SXT hard reset) you may very well see it occur again the next time the system tries to regenerate.

    The most common cause of the Err 0 error code is a jammed piston. A jammed piston will occur if there is excessive deposition of iron or other foulants (like manganese) on the internal components of the control valve preventing it from moving freely. If there has been damage to one of the internal seals this may also interfere with the ability of the piston to move, causing the Err 0 code as well.

    If you suspect a a jammed piston is the issue, we recommend replacing the internal components with the purchase of a Fleck 5600SXT Softener Rebuild Kit. If your Fleck 5600 is being used on backwashing filter, there's the Fleck 5600SXT Filter Rebuild Kit.

    Error Code "Err 1"

    The Err 1 code is generated when the motor continuously runs. This is often caused when the motor is not properly set in the motor mount and it is not engaging properly with the gears of the system. It may also be caused if the piston drive linkage is not assembled. Lastly, it may be cause if an internal micro switch is not being depressed properly or if this microswitch has failed. In the Fleck 5800 and 5810 it may be caused by issues with the optical sensor.

    Error Code "Err 2"

    The Err 2 code is generated when the system has failed to do a regeneration (in the case of water softeners) or a backwash (in the case of filter units) for more than 99 days. This error code can be cleared by manually initiating a regeneration by pressing and holding the "next cycle" on the controller:

    fleck 5600 water softener controller

    Even though this will clear the Err 2 error code, you'll probably want to have a look at the programming of the system to make sure you have a Day Override (DO) value set to any value except zero.

    Error Code "Err 3"

    The Err 3 error code is generated when there is a memory error on the board of the Fleck 5600SXT controller. Here are instructions you can follow to do a hard reset of the board and to discharge the "super capacitor" on the board. If these instructions are followed, and the error code is not cleared then the board has failed and needs to be replaced.

    If you're not able to fix the problem with your Fleck 5600, you can view our selection of new softeners here.

    Error Code "Err 4"

    The Err 4 error code is generated when the SXT controller has not received a signal that the piston is in the expected position. This can be caused for a number of reasons with the most common being:

    • Control Board Error
    • Jammed Piston
    • Dirty / Misaligned / Faulty Optical Sensor

    To rectify this error code (or to determine if it's accurate) you first need to eliminate a circuit board error. To do this, follow these instructions:

    This process wipes all settings from the board and resets it to factory defaults. So, after the process is done, the board will need to be re-programmed.

    Once this is complete, force the system into a regeneration by pressing and holding the NEXT CYCLE button which is the leftmost button on the controller until you hear the motor engage, then release it.

    When you see a countdown, press this same button once to advance to the next stage. You can do this at each stage to step it through a full regeneration sequence. This can be done with the valve cover removed to visually confirm that the valve mechanism is moving, but be careful that you do not touch any electrical components as they will be live / hot.

    If the piston is moving well it is likely the optical sensor that is the culprit (5800 / 5810 / 5812 only). Refer to the owner's manual to locate and service the optical sensor on these systems.