E16 error and the unit indicates an excessive regeneration frequency or capacity calculation fault

Safety first: Ensure safe access to all isolation valves and plumbing before making changes.

• Review settings: Check the programmed hardness and capacity values. Compare with a hardness test of the incoming water and adjust if necessary.
• Check for leaks: With all taps closed, look at the flow indicator on the Monarch display. If it shows flow when no water is being used, there may be a leak or running toilet downstream.
• Inspect bypass arrangement: Confirm the three-valve bypass set is correctly positioned and that there is no cross-connection between hard and soft lines.
• Test flow meter: Run a known volume of water and compare the meter reading. If it over-registers significantly, the flow meter may be faulty and require replacement.