E14 error; unit runs but does not heat water (for models with onboard heater)

Safety first: Unplug the carpet cleaner and allow any heater components to cool before working. Heater circuits involve mains voltage.

• 1. Confirm model has heater
  • Check the rating label or manual to ensure your Bosch carpet cleaner includes a water heater.
• 2. Access heater assembly
  • Remove covers to locate the heater block, usually in-line with the solution hose.
  • Inspect for burn marks or signs of overheating.
• 3. Test heater element
  • Disconnect heater terminals.
  • Measure resistance with a multimeter; an open circuit indicates a failed element.
  • Replace the heater assembly if open or shorted.
• 4. Check thermal fuse and NTC
  • Locate the thermal fuse and temperature sensor attached to the heater.
  • Test continuity of the thermal fuse; if open, replace it and investigate cause of overheating.
  • Measure NTC resistance and compare with Bosch specifications; replace if out of range.
• 5. PCB heater relay
  • If heater and sensors are good, the relay or triac on the control PCB may be faulty.
  • Due to mains hazards, PCB repair or replacement should be done by a professional.