Heater does not warm solution; E5 error appears after a few minutes of operation.

Safety first: Unplug the unit and allow it to cool completely before accessing the heater assembly. Hot surfaces can cause burns.

• Check for restricted flow: Low water flow can cause heater overheat. Ensure the clean water tank is full, seated correctly, and that the solution lines and spray nozzles are not blocked.
• Access the heater block: Remove the side or bottom cover to expose the aluminum heater block and its wiring. Note the position of all connectors before disconnecting.
• Test the heater element: With a multimeter, measure resistance across the heater terminals. An open circuit indicates a failed heater that must be replaced.
• Inspect the thermal fuse and thermostat: Many Rowenta heaters include an inline thermal fuse or thermostat. Test for continuity. If open, replace with the exact temperature and current rating specified.
• Check the NTC sensor: Measure the resistance of the NTC temperature sensor at room temperature and compare with service data if available. A shorted or open NTC will trigger E5.
• Reassemble and test: After replacing any faulty heater components, reassemble the housing, refill the tank, and test for proper heating without error.