Vaillant Fault Codes

Vaillant Boilers

Vaillant Fault Codes

As Vaillant approved engineers and with Vaillant being one of the most popular boiler makes that we install, should your boiler develop a fault, it’s likely that it will display an error code. All of these codes can assist us when your first call us and ensure that we get the right part and the right engineer out to you first time.

F0 = Flow NTC open circuit
F1 = Return NTC open circuit
F10 = Flow NTC short circuit
F11 = Return NTC short circuit
F13 = Tank NTC short circuit
F20 = Safety temperature limiter by NTC activation
F22 = Dry fire
F23 = Water shortage, temperature difference between the flow and return NTC is too large
F24 = Water shortage, temperature rise is too quick
F25 = Interruption in the compact thermal module cable harness
F27 = Incorrect sensing of flame
F28 = Appliance does not start: Attempts to ignite during start failed
F29 = Flame goes off during operation and subsequent ignition attempts failed
F32 = Fan speed variation
F49 = eBUS undervoltage
F61 = Gas valve control defective
F62 = Gas valve shutoff delay
F63= EEPROM error
F64 = Electronics or NTC fault
F65 = Electronics temperature rise too fast
F67 = Flame detection input signal is outside designed limits
F70 = No valid DSN in display or mainboard
F71 = Flow NTC reports a constant value
F72 = Flow and/or return NTC fault
F73 = Water pressure sensor signal is too low
F74 = Water pressure sensor signal is too high
F75 = No pressure rise was detected on turning on the pump
F76 = Overheat protection on primary heat exchanger triggered
F77 = Condensate pump or feedback of accessories block
F78 = Wrong accessory configuration
con = No communication to main board

Should your Vaillant boiler develop a fault and you live in London or it’s surrounding areas you should give us a call on 0208 348 4729 to see if we can help. Our qualified Gas Safe Registered engineers carry the majority of modern Vaillant parts on their vans and will aim to get you running again that very same visit.

Of course, from the above fault list, there are a few things that you should check yourself before calling in the cavalry:

  • F75 and F22, F23, F24
    Make sure that your boiler’s system pressure is between 1 and 1.5Bar, top your system up with the filling loop as required.
  • F28 and F29
    Is your gas on? Is any work being carried out in the street and if you have a pay as you go gas meter, do you have enough credit?