Fault Codes; Fault Memory - Vaillant ecoTEC plus Instructions For Installation And Servicing

10 Troubleshooting

10.1.3 Fault codes

Fault codes take priority over all other display functions
in the event of a system fault occurring.If multiple faults
occur, the corresponding fault codes are displayed alter-
nately for about two seconds each.

10.1.4 Fault memory

The fault memory stores details of the ten most recent faults.
Code Meaning
F. 0 Flow–NTC open circuit
F. 1 Return–NTC open circuit
F.10 Flow NTC short circuit
F.11 Return NTC short circuit
F.13 Tank NTC short circuit
F.20 Safety temperature limiter by NTC activated
F.22 Dry fire
F.23 Water shortage, temperature difference
between flow and return NTC too large
F.24 Water shortage, temperature rise too quick
F.27 Incorrect sensing of flame
F.28 Appliance does not start: Attempts to
ignite during start failed
F.29 Flame goes off during operation and
subsequent
F.32 Fan speed variation
F.49 eBUS under voltage
F.61 Gas–valve control defective
F.62 Gas valve shut off delay
F.63 EEPROM error
F.64 Electronics/NTC fault
F.65 Electronics temperature too high
F.67 Flame detector input signal is outside the
limits (0 or 5 V)
F.70 No valid DSN in display and/or main board
F.71 Flow NTC reports constant value (stuck at)
F.72 Flow and/or return NTC fault
F.73 Water pressure sensor signal out of range
(too low)
F.75 No pressure rise was detected on turning
on the pump
F.76 Overheating protection on primary heat
exchanger triggered
F.77 Condensate pump or feedback of
accessories blocks heating
F.78 Wrong configuration with accessory
con No communication to main board
Table 10.4 Error codes
36
• Press the "i" and "–" buttons simultaneously.
• Use the "+" button to scroll back through the list of
memorised errors. To cancel fault error memory dis-
play mode, proceed as follows:
• Press the "i" button below the display or
• Do not touch any key for about four minutes. The dis-
play will now revert back to showing the current flow
temperature.
Cause
NTC broken, NTC cable broken, Defective connection at NTC, Defective connec-
tion at electronics
NTC broken, NTC cable broken, Defective connection at NTC, Defective connec-
tion at electronics
NTC defective, short circuit in cable harness, cable/casing short cut
NTC defective, short circuit in cable harness, cable/casing short cut
NTC defective, short circuit in cable harness, cable/casing short cut
Flow-NTC not correctly thermal-connected or defective; appliance does not shut down
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
Pump blocked or defective, pump output too low, flow and return NTC interchan-
ged
Pump blocked, insufficient pump output, air in appliance, water pressure too low
Flame detector defective
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
ignition attempts failed Gas supply temporarily stopped, faulty earthing of appli-
ance
Fan blocked, plug not inserted correctly on fan, hall sensor defective, fault in
cable harness, electronics defective
Short circuit on eBUS, overload on eBUS or two power sources on eBUS with dif-
ferent polarity
Short circuit/earth (ground) leak in cable harness to gas valves, gas valve assembly
defective (earth/ground leak from coils), electronic control system defective
Gas valve leaking, electronics defective
Electronics defective
Short-circuit in flow or return NTC or electronics defective
Electronics too hot due to external effect, electronics defective
Electronics defective
Spare part failure display and main board interchanged at same time and device
specific number not adjusted
Flow NTC is defective
Flow and/or return NTC is defective (tolerances too big)
Spare part failure display and main board interchanged at same time and device
specific number not adjusted
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
Cable or cable connection of fuse in the primary heat exchanger defective, or pri-
mary heat exchanger defective
Condensate pump defective or flume flap feedback triggered
link box VR65 connected to combination boiler
Connection error display main board
Instructions for installation and servicing ecoTEC plus / 0020020828_05