Heater overheats, very hot solution or steam at wand, E9 displayed and heater shuts off

Safety: Unplug and allow the heater and solution lines to cool fully. Hot solution can cause burns.

• Check solution flow:
  • Ensure the solution tank is full and the intake filter is clean.
  • Verify that spray jets are not blocked, allowing adequate flow through the heater.
• Bleed air from heater:
  • After cooling, run the pump with heater off for 1–2 minutes to purge air from the heater and lines.
• Inspect heater thermostat and sensor:
  • Access the in-line heater assembly.
  • Test the thermostat and temperature sensor (if separate) according to the service manual.
  • Replace the heater assembly or temperature sensor if readings are out of specification.
• Do not bypass safety devices:
  • Never bridge out thermostats or thermal fuses; this is dangerous and voids safety approvals.