Vaillant Ecotec Plus 615 Boiler Fault Codes

Vaillant Boilers
 Code Meaning Cause
F0 Flow–NTC open circuit NTC broken, NTC cable broken, Defective connection at NTC, Defective connection at electronics
F1 Return–NTC open circuit NTC broken, NTC cable broken, Defective connection at NTC, Defective connection at electronics
F10 Flow NTC short circuit NTC defective, short circuit in cable harness, cable/casing shortcut
F11 Return NTC short circuit NTC defective, short circuit in cable harness, cable/casing shortcut
F13 Tank NTC short circuit NTC defective, short circuit in cable harness, cable/casing shortcut
F20 Safety temperature limiter by NTC activated Flow-NTC not correctly thermal-connected or defective; appliance does not shut down
F22 Dry fire Too little water in the appliance, water pressure sensor defective, cable to pump or water sensor defective, pump blocked or defective, pump output too low
F23 Water shortage, temperature difference between flow and return NTC too large Pump blocked or defective, pump output too low, flow and return NTC interchanged
F24 Water shortage, temperature rise too quick Pump blocked, insufficient pump output, air in appliance, water pressure too low
F25 Interruption in the compact thermal module cable harness Compact thermal module cable harness defective
F27 Incorrect sensing of flame Flame detector defective
F28 Appliance does not start: Attempts to ignite during start failed

Faults in the gas supply such as:

- Gas meter or gas pressure detector defective

- Air in gas

- Gas flow pressure too low

- Fire protection tap has disengaged

Faults in the gas valve, wrong gas setting, igniter (ignition transformer, ignition cable, ignition plug) defective, ionisation current stopped (cable, electrode), faulty earthing in appliance, electronics defective

F29 Flame goes off during operation and subsequent ignition attempts failed Gas supply temporarily stopped, faulty earthing of appliance
F32 Fan speed variation Fan blocked, plug not inserted correctly on fan, hall sensor defective, fault in cable harness, electronics defective
F49 eBUS undervoltage Short circuit on eBUS, overload on eBUS or two power sources on eBUS with different polarity
F61 Gas–valve control defective Short circuit/earth (ground) leak in cable harness to gas valves, gas valve assembly defective (earth/ground leak from coils), electronic control system defective
F62 Gas valve shutoff delay Gas valve leaking, electronics defective
F63 EEPROM error Electronics defective
F64 Electronics/NTC fault Short-circuit in flow or return NTC or electronics defective
F65 Electronics temperature too high Electronics too hot due to external effect, electronics defective
F67 Flame detector input signal is outside the limits (0 or 5 V) Electronics defective
F70 No valid DSN in display and/or mainboard Spare part failure display and maiboard interchanged at same time and device specific number not adjusted
F71 Flow NTC reports constant value (stuck at) Flow NTC is defective
F72 Flow and/or return NTC fault Flow and/or return NTC is defective (tolerances too big)
F73 Water pressure sensor signal out of range (too low) Cable to water pressure sensor is broken or has a short-circuit at 0 V or water pressure sensor defective
F74 Water pressure sensor signal out of range (too high) Cable to water pressure sensor has a short-circuit at 5 V / 24 V or internal fault in water pressure sensor
F75 No pressure rise was detected on turning on the pump Water pressure sensor or/and pump defective Air in the heating system, quick bleeder defective Too little water in appliance; check adjustable by-pass; connect external expension vessel to return
F76 Overheating protection on primary heat exchanger triggered Cable or cable connection of fuse in the primary heat exchanger defective, or primary heat exchanger defective
F77 condensate pump or feedback of accessory blocks heating condensate pump defective or flume flap feedback triggered
F78 wrong configuration with accessory link box VR65 connected to combination boiler
con no communication to mainboard connection error display mainboard