F41 displayed, appliance may not regulate power correctly

Safety first: Isolate power and allow the unit to cool.

• Check sensor mounting: Ensure the flow NTC is firmly attached to the pipe or in its pocket with thermal paste if specified.
• Inspect wiring: Keep sensor cables away from high-voltage or ignition cables.
• Replace NTC: If readings are unstable or out of tolerance, replace the flow NTC sensor.
• PCB check: If a new sensor does not resolve F41, the PCB input may be faulty.

Warning: Incorrect temperature control can lead to scalding or poor performance; verify operation after repair.