Vaillant EcoTEC Pro, EcoFIT Pure & EcoTEC Plus Boiler Error Codes

Vaillant’s award-winning combination, system and open vent boilers are renowned for their reliability, performance and efficiency.

Sometimes things can go wrong, so we’ve created a handy table of Vaillant boiler error codes below.

F – Fault Code	Possible Cause
F.0/F.00	Flow temperature sensor interruption
F1./F.01	Return temperature sensor interruption
F.10	Flow NTC short circuit
F.11	Return NTC short circuit
F.20	Safety switch off temperature limiter
F.22	Safety switch off low water pressure
F.23	Safety switch off temperature difference too great
F.24	Safety switch off temperature is rising to fast
F.25	Safety switch off flue gas temperature too high
F.26	Error with gas valve – possible no function
F.27	Safety switch off flame simulation
F.28	Failure during start up – ignition unsuccessful to start
F.29	Failure during operation – re-ignition unsuccessful
F.32	Fan error
F.49	eBUS error – possible short circuit
F.61	– Error with gas valve regulation
F.62	Error with gas valve – switch off delay
F.63	EEPROM error
F.64	Electronics / NTC error
F.65	Electronic temperature error could be overheating due to external influences
F.67	Electronics flame signal error
F.68	Unstable flame signal error air in gas
F.70	Invalid device specific number (DSN)
F.71	Flow NTC error – flow temperature sensor signal constant value
F.72	Flow return NTC error – temperature difference too great
F.73	Water pressure sensor signal in the wrong range, it is too low
F.74	Water pressure sensor signal outside correct range, the sensor signal is too high
F.75	Error with pressure – no pressure change detection when starting the pump
F.76	Overheating protection on – primary heat exchanger has responded
F.77	Flue non return flap condensate pump error
F.78	Interruption to DHW outlet sensor at external controller
F.83	Flow and or return temperature sensor error
F.84	Error with flow/return temperature sensor temperature changing error
F.85	Error with flow and return temperature, sensor incorrectly fitted
CONNECTION	No communication with the PCB

S – Fault Code	Possible Cause
S.00	Heating mode error – no heat demand
S.01	Heating mode fan start-up
S.02	Heating mode error – water pump running
S.03	Heating mode – ignition sequence error
S.04	Heating mode – burner ignited
S.06	– Heating mode – fan overrun error/td>
S.07	Heating mode – pump overrun error
S.08	Heating remaining cut off time xx minutes
S.10	Hot water demand via impeller sensor
S.11	DHW mode fan start up error
S.13	DHW mode ignition error
S.14	Hot water demand via fan sensor error
S.15	DHW mode pump and fan overrun
S.16	DHW mode – fan overrun error
S.17	DHW mode – pump overrun error
S.20	DHW mode – burner on error
S.21	DHW mode – fan start up error
S.22	DHW demand – error pump running
S.23	DHW ignition error
S.24	DHW mode – burner error
S.25	DHW mode – pump or fan overrun error
S.26	DHW mode – fan overrun
S.27	DHW mode – pump overrun
S.28	Hot water burner anti-cycling time
S.30	Room thermostat is blocking heating mode
S.31	No heat demand boiler in summer operating mode
S.32	Waiting period because of fan speed deviation
S.34	Heating mode frost protection error
S.39/td>	Burner off contact has been triggered this could be because of contact thermostat or condensate pump
S.40	Comfort safety mode active
S.41	Water pressure > 2.8 bar
S.42	Flue non return flap return signal blocks burner operation
S.46	Comfort safety mode flame loss at minimum load
S.53	Boiler is in waiting period of modulation f block function due to water shortage
S.54	Boiler is in waiting period of operation, blocking function as a result
S.57	Waiting period comfort safety mode
S.58	Modulation limitation due to noise / wind error
S.61	Gas family check unsuccessful