E03 displayed and the softener does not refill the brine tank at the end of regeneration

Safety first: Isolate electrical supply and close inlet/outlet valves before dismantling the valve head.

• Confirm water supply: Ensure the inlet valve is fully open and household pressure is normal. Low pressure can prevent proper refill.
• Inspect refill line and elbow: On some Monarch models, a small refill elbow and restrictor feed the brine tank. Remove the line at the valve and check for blockages or scale. Clean or replace as needed.
• Clean refill restrictor: Locate the refill flow restrictor (often a small plastic insert or orifice in the valve body). Remove carefully, soak in descaling solution, rinse, and reinstall.
• Check valve operation: Run a manual regeneration and listen for the valve motor/solenoid during the refill stage. If silent or obviously not moving, the motor section or solenoid may be defective.
• Manual top-up: As a temporary measure, manually add the correct amount of water to the brine tank (per Monarch specification) so the unit can soften until a permanent repair is made.