F.00 Meaning
This fault according to Vaillant Instructions and Servicing manual is a Heating Flow Temperature Sensor interruption or Heating Flow NTC Thermistor fault.
Cause of F00
The cause of this fault is that either the
- Heating Flow NTC Thermistor has become disconnected Or Has Gone Open Circuit (Should Read 12Kohms @ 20C), or
- Wiring Harness Fault Or Connection Error Between The Heating Flow NTC Thermistor And The Main PCB
Solutions to repair this fault
Test the NTC sensor, test the connection between the NTC sensor and the PCB ie the wiring harness. Unplug and replug as necessary. Replace the NTC if necessary. Replace the harness if necessary.
