Display shows E05 and the control valve motor does not complete its cycle

Safety first: Isolate power before removing the control valve cover. Water pressure should be isolated and relieved if you intend to remove the valve head.

Step-by-step checks:

• 1. Listen for motor operation: With the cover on and power restored, initiate a manual regeneration. Listen for the motor running. If silent, suspect motor or power supply.
• 2. Inspect wiring and connectors: Remove the control valve cover. Check the motor plug and cam sensor/limit switch connectors. Reseat them firmly.
• 3. Check for mechanical jam: With power off, gently try to rotate the cam gear (if accessible) by hand. It should move with some resistance. If completely stuck, the piston may be seized due to scale or debris.
• 4. Test motor (if competent): Using a multimeter and following the service manual, verify that the motor receives the correct voltage during a cycle. If voltage is present but the motor does not turn, replace the motor.
• 5. Inspect cam switch/sensor: Ensure the cam follower or sensor is correctly aligned with the cam and not bent or broken. A failed sensor can prevent the control from seeing the correct position.

Because this fault involves moving parts and pressurised components, if you are not experienced with valve disassembly, contact a Scalemaster-approved technician to replace the motor, piston, or cam assembly.