E09 displayed and the unit reports a resin tank pressure or leak fault (on models with pressure sensor)

Safety first: Immediately disconnect power and close the inlet valve. Do not continue using the softener until leaks are located and repaired.

• Inspect cabinet base: Remove the front cover and check for standing water in the base. Many Monarch units have a leak pad or float switch; dry the area thoroughly if wet.
• Check all unions: Examine the connections at the inlet, outlet, and drain ports on the valve head. Tighten any loose nuts by hand, then a further quarter turn with a spanner if needed. Do not overtighten plastic fittings.
• Inspect resin vessel: Look for cracks, bulges, or signs of stress on the resin tank, especially around the neck where it joins the valve.
• Reset leak sensor: Once fully dry and any leaks are corrected, reset the leak sensor according to the Monarch manual (often by pressing and holding a specific button sequence).
• Monitor operation: Restore water and power, then observe the unit through a full regeneration cycle to ensure no further leaks occur.