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 NTC Thermistor Fault or Heating Return NTC short circuit
Cause of F11
There Is A Short Circuit On The Heating Return NTC Thermistor (Should Read 12Kohms @ 20C)
Wiring Harness Fault Or Connection Error Between The Heating Return NTC Thermistor And The Main PCB.
Solutions to repair this fault
Check the NTC sensor. Check the wiring using a continuity tester and resistance tester if necessary. Replace NTC, harness or PCB as necessary dependent on checks.
Models applicable to:
Ecotec Pro, Ecotec Plus, Ecotec Exclusive.
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