Welcome to the fault-codes section of this site. The following table or page contains the information required to help repair and diagnose the fault codes being shown on the boiler display. You may be guided through the fault finding sequence or steps, for rectifying your boiler with this fault code. Suggested repair solutions may be provided by a link to a repair page. NB Some fault codes are only applicable to a specific range of boilers only.
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.
Disclaimer: Information on this website is provided for informational purpose therefore we cannot accept liability for subsequent problems. All repair tasks should be carried out by qualified trades people.
We may also receive commission payments when you are taken to external websites and complete purchases from third party sellers, once you leave our site, we cannot be held liable for your purchases.