Marey heater displays E5 and stops heating; may occur when multiple fixtures are used.

Safety first: Turn OFF power and close the cold-water supply. Open a hot tap to relieve pressure.

Steps:

• Bleed air from lines: With power OFF, open several hot water taps to purge trapped air. Close them and then reopen one tap while testing later.
• Clean inlet filter: Remove and clean the cold inlet mesh filter screen to ensure proper flow.
• Inspect flow meter: Remove the front cover and locate the flow meter assembly (often on the cold inlet). Check for visible scale or debris. If accessible, remove the flow meter and rinse the turbine under water until it spins freely.
• Check wiring: Ensure the flow meter’s Hall sensor connector is fully seated on the control board and wires are not pinched.
• Replace flow meter if needed: If the turbine is damaged or the Hall sensor tests bad (no pulse output), install a new Marey flow meter assembly.

When to call a technician: If you are not comfortable removing plumbing connections or testing sensors with a multimeter.