Display shows “Err 5” and the valve appears to be in a constant regeneration or locked state.

Safety first: Unplug the unit before extended programming or wiring checks.

• Verify meter type: Enter programming mode and confirm the correct meter type is selected (e.g., turbine, paddle wheel, cable length) for your Fleck meter assembly.
• Check auxiliary wiring: If using external switches or relays, verify they are wired according to the Fleck wiring diagram and not shorting inputs.
• Factory reset: Perform a factory reset of the control and re-enter all settings (hardness, capacity, day override, regeneration time).
• Update or replace control: If Err 5 returns after correct programming, the control board may be defective and should be replaced.