Display shows “Err 05” and unit will not advance through regeneration stages

Safety first: Unplug the softener and shut off water. Bypass the unit before disassembly.

Step-by-step checks:

• 1. Access the position switch:
  • Remove the top cover.
  • Locate the position switch or encoder mounted near the rotor/cam on the valve head.
  • Inspect the small switch arm or sensor for damage or misalignment with the cam notches.
• 2. Mechanical alignment:
  • Manually rotate the rotor/cam (with power off) and verify that the switch actuates at each detent.
  • If the switch does not click or the encoder wheel does not pass through the sensor properly, adjust or replace the assembly.
• 3. Electrical inspection:
  • Check the harness from the switch/encoder to the control board for pinched or broken wires.
  • Reseat the connector on the control board.
• 4. Replace if needed:
  • If the switch does not change state when actuated (test with a multimeter if qualified), replace the position switch / encoder assembly.
  • If a new switch does not clear Err 05, the control board may not be reading the signal and should be replaced.