Fleck 5800 & 5810 Err 1 from Optical Sensor Issues

The controller on the Fleck 5800 and 5810 systems will sometimes display an error code. The error code "Err 1" is displayed when the controller is unable to confirm that the mechanical valve has been moved into the "home" position. The home position is the position of the valve when the softener is not regenerating. There are many different reasons that the system may not be able to find the home position that we cover in this Fleck 5600 / 5800 / 5810 troubleshooting article, but issues with the optical sensor are difficult to find information on, so we wanted to produce an article that speaks specifically to this issue.

The Fleck 5800 and 5810 control valves use an indexing disc and an optical sensor to determine the position of the piston inside the valve body. The image below shows these components in an exploded view. The Indexing Disc (1) sits between the two posts of the Optical Sensor (2) which is held in place by the Retaining Clip (3):

The Optical Sensor (2) is comprised of two posts.  One post produces light and the second post receives this light signal. The egde of the Indexing Disc (1) is slotted and allows light to pass through these slots as it spins. This allows the system to detect positioning of the physical components of the valve mechanism.

There are several ways that this system can fail:

• The optical sensor can become dislodged from its position (usually caused by being jostled in transit).
• The optics of the optical sensor can become dirty in high-dust or high-condensation environments
• The retaining clip is not pushed down into its fully seated position
• When the power head it taken apart and put back together, the indexing disc is not positioned properly between the two posts of the Optical Sensor