Vaillant EcoTEC Gas Boiler Diagnostic codes

Vaillant EcoTEC Gas Boiler Error Codes

Fault Code Possible Cause
D.0 Heating part load error
D.1 Water pump overrun – time for heat mode
D.2 Max burner anti-cycling period at 20c flow temperature
D.3 Hot water flow temperature reading
D.4 Current temperature for warm stat sensor
D.5 Set value of flow temperature or target value of return
D.7 Warm start temperature target value
D.8 External controls heat demand
D.9 Flow target temperature from external analogue regulator terminal
D.10 Status internal heating pump error
D,11 Status external heating pump error
D.12 Cylinder charging pump via accessory module
D.13 Hot water circulation pump
D.15 Pump speed actual value
D.22 Hot water demand
D.23 Summer/Winter function
D.24 Not relevant
D.25 Hot water activation via eBus control
D.30 Control signal for both gas valves
D.33 Fan speed target value
D.34 Fan speed actual value
D.35 Not relevant
D.40 Flow temperature target value
D.41 Return temperature actual value
D.44 Digitised ionisation – potential error
D.47 Outside temperature with weather compensator – Vaillant controller only
D.76 Remaining burner anti-cycling time in min
D.90 Digital regulator status
D.91 DCF status with connected external probe
D.97 Activation of the second diagnostic level
D.98 Telephone a heating engineer
D.14 Pump speed target value
D.17 Heating flow return regulation
D.18 Pump operating mode
D.20 Maximum set value for target cylinder
D.26 Additional relay control ecoTec
D.27 Switching accessory relay 1
D.28 Switching accessory relay 2
D.50 Offset for minimum speed
D.51 Offset for maximum speed
D.60 Number of safety temperature cut offs
D.61 Number of unsuccessful lockouts
D.64 Average ignition times
D.65 Maximum ignition time
D.67 Remaining burner anti-cycling time
D.68 Unsuccessful ignitions in the first attempt
D.69 Unsuccessful ignition for the second time
D.70 Set diverter valve position
D.71 Maximum setting of heater control knob
D.72 Pump overrun time after warm start
D.75 Maximum charging time for a storage without own controller
D.77 Limitation of cylinder charging in output in kW
D.78 Limitation of cylinder charging temperature in celsius
D.80 Operating hours heating
D.81 Operating hours hot water generation
D.82 Burner start up in heating mode
D.83 Burner start up in hot water mode
D.84 Maintenance indicator – number of hours until the next maintenance
D.93 DSN appliance variant setting
D.96 Factory setting

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