Panasonic water heater shows H05 and stops; water may briefly warm then go cold.

Safety: Turn OFF power and close the cold water inlet valve before removing any water connections.

• 1. Check minimum flow:
  • Open a hot water tap fully. If the flow is very low, the heater may not detect flow.
  • Clean faucet aerators and shower heads to restore flow.
• 2. Clean inlet water filter:
  • Close the cold water inlet valve to the heater.
  • Locate and remove the inlet filter screen (usually at the cold inlet union).
  • Rinse debris and scale under running water and reinstall.
• 3. Reset and test: Restore water and power, then open a hot tap to see if H05 clears.
• 4. Inspect flow sensor (qualified persons):
  • Remove the front cover.
  • Locate the flow sensor on the cold inlet pipe.
  • Check wiring harness for secure connection and damage.
• 5. Descale or replace flow sensor:
  • If scale is heavy, the flow sensor body may need to be removed and soaked in descaling solution (follow Panasonic guidelines).
  • If the turbine does not spin freely, replace the flow sensor assembly.