Vaillant ecoTEC plus 612, Instructions For Installation And Servicing

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Instructions for installation and servicing ecoTEC
Code Meaning Cause
F.25 Interruption in the compact thermal module cable har-
ness 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 trans-
former, 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 defec-
tive, 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 expension vessel to return
F.76 Overheating protection on primary heat exchanger trig-
gered Cable or cable connection of fuse in the primary heat exchanger
defective, or primary heat exchanger defective
F.77 condensate pump or feedback of accessorie blocks heat-
ing 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 mainboard connection error display mainboard
Table 8.4 Error codes (continued)
Troubleshooting 8