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Vaillant F23 Fault Code

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.

F.23 Meaning

This fault according to Vaillant Instructions and Servicing manual is a Heating Flow NTC Thermistor Fault or Heating Flow NTC short circuit

Cause of F23

  • Inadequate Pump Operation
  • Blockage Or Air Lock Within The Appliance (No Water Movement)
  • Blockage Or Air Lock In The Heating System (No Water Movement)
  • Check Domestic Hot Water Heat Exchanger and Domestic Hot Water Heat Exchanger Filter For Debris If Fault Occurs On Hot Water Mode Only
  • Check Resistance On The Heating Flow & Return NTC Thermistors To Ensure Accurate Temperature Monitoring (Should Read 12K ohms @ 20C

 

Solutions to repair this fault

Check the Flow and return NTC sensors. Check the wiring using a continuity tester and resistance tester if necessary. Replace NTC, harness or PCB as necessary dependent on checks.

Make sure there are no blockages in the pipework.  If there is debris in the system, flushing may be required. Then individual components may require cleaning or replacing dependent on damage caused by debris.  You may need to activate the pump purge program (see P Codes). Also check the domestic heat exchanger is free of debris, cleaning the filter as necessary.

Vaillant Flow / Return NTC 193592

Vaillant NTC Sensor

Models applicable to:

Ecotec Pro, Ecotec Plus, Ecotec Exclusive.

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.