THE FOLLOWING LISTS THE FAULT CODES FOR THE VAILLANT ECOTEC RANGE OF BOILERS , JUST CHECK WHAT THE BOILER DISPLAY IS SHOWING, IT SHOULD BE A F WITH A NUMBER FOLLOWING IT. THEN COMPARE IT WITH THE LIST AND IT WILL SHOW YOU WHAT THE MEANING AND THE CAUSE OF THE FAULT IS.
PLEASE NOTE THAT YOU MUST BE GAS SAFE REGISTERED TO WORK ON GAS APPLIANCES, PLEASE CALL US IF YOU ARE UNSURE AND WE CAN ADVISE OR SEND A ENGINEER TO REPAIR THE BOILER.
Code. Meaning. & Cause
F. 0 Flow–NTC open circuit
NTC broken, NTC cable broken, Defective connection at NTC,
Defective connection at electronics
F. 1 Return–NTC open circuit NTC broken, NTC cable broken, Defective connection at NTC,
Defective connection at electronics
F.10 Flow NTC short circuit NTC defective, short circuit in cable harness, cable/casing shortcut
F.11 Return NTC short circuit NTC defective, short circuit in cable harness, cable/casing shortcut
F.13 Tank NTC short circuit NTC defective, short circuit in cable harness, cable/casing shortcut
F.20 Safety temperature limiter by NTC activated
Flow-NTC not correctly thermal-connected or defective; appliance
does not shut down
F.22 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
F.23 Water shortage, temperature difference between flow
and return NTC too large
Pump blocked or defective, pump output too low, flow and return
NTC interchanged
F.24 Water shortage, temperature rise too quick
Pump blocked, insufficient pump output, air in appliance, water
pressure too low
F.25 interruption in the compact thermal module cable harness
Compact thermal module cable harness defective
F.27 Incorrect sensing of flame Flame detector defective
F.28 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
F.29 Flame goes off during operation and subsequent ignition
attempts failed
Gas supply temporarily stopped, faulty earthing of appliance
F.32 Fan speed variation
Fan blocked, plug not inserted correctly on fan, hall sensor
defective, fault in cable harness, electronics defective
F.49 eBUS undervoltage
Short circuit on eBUS, overload on eBUS or two power sources on
eBUS with different polarity
F.61 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
F.62 Gas valve shutoff delay Gas valve leaking, electronics defective
F.63 EEPROM error Electronics defective
F.64 Electronics/NTC fault Short-circuit in flow or return NTC or electronics defective
F.65 Electronics temperature too high Electronics too hot due to external effect, electronics defective
F.67 Flame detector input signal is outside the limits
(0 or 5 V)
Electronics defective
F.70 No valid DSN in display and/or mainboard
Spare part failure display and maiboard interchanged at same time
and device specific number not adjusted
F.71 Flow NTC reports constant value (stuck at) Flow NTC is defective
F.72 Flow and/or return NTC fault Flow and/or return NTC is defective (tolerances too big)
F.73 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
F.74 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
F.75 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 expansion vessel to return
F.76 Overheating protection on primary heat exchanger triggered
Cable or cable connection of fuse in the primary heat exchanger
defective, or primary heat exchanger defective
F.77 condensate pump or feedback of accessories blocks heating
condensate pump defective or flume flap feedback triggered
F.78 wrong configuration with accessory link box VR65 connected to combination boiler
con no communication to main board connection error display main board