Water remains hard at taps even though the Cillit softener appears to run normally (no error code)

Safety: No electrical work is required. Close taps before adjusting valves.

• Check bypass position: Locate the Cillit bypass assembly (often a three‑valve block). Ensure the inlet and outlet valves are fully open and the bypass valve is fully closed.
• Adjust blending valve: If your Cillit model has a hardness blending valve, slowly close it while testing hardness at a tap using a Cillit hardness test kit until the desired residual hardness is reached.
• Verify plumbing: Confirm that the softener is installed only on the cold supply to the house (or as specified) and that no cross‑connections allow untreated water to mix downstream.
• Internal leak check: If hardness remains high with bypass closed and plumbing correct, an internal bypass seal in the valve head may be leaking. This requires disassembly and replacement of the Cillit valve seal and spacer kit.