Water heater occasionally fails to start when a tap is opened, but works again after closing and reopening the tap.

Safety: Turn off power before opening the unit.

• Increase flow for testing: Fully open the hot tap and avoid mixing with cold to ensure maximum flow.
• Clean inlet filter: Remove and clean the inlet filter screen to reduce restriction.
• Clean flow sensor: Inspect and clean the flow sensor turbine and housing to ensure smooth rotation.
• Purge air: Open multiple hot taps to purge any trapped air from the system.
• Monitor: If intermittent failures continue, the flow sensor may need replacement.