E05 displayed, unit stuck in regeneration and water supply may be interrupted

Safety: Turn off power and isolate the softener with bypass valves before working on the valve head.

• Check bypass: Place the Cillit bypass valve in bypass position to restore water to the house while you work.
• Inspect cam and switches: Remove the control head cover. Observe the main cam wheel and the small microswitches or optical sensors around it. Look for broken plastic tabs, loose screws, or bent switch levers.
• Realign cam: If the cam has slipped on its shaft, follow the Cillit service procedure to set the valve to the “service” position manually, then reposition the cam so its reference mark aligns with the service index on the housing.
• Test switches: With a multimeter, check continuity of each position switch while slowly rotating the cam by hand (power off). Replace any switch that does not change state reliably.
• Clear obstructions: If the rotor cannot complete its travel, there may be debris inside the valve. This requires disassembly of the Cillit valve body, cleaning of seals and spacers, and reassembly with new Cillit seal and spacer kit if worn.