Vaillant ecoTEC plus 612 Instructions For Installation And Servicing page 46

8 Troubleshooting
Code Meaning
F. 0 Flow–NTC open circuit
Return–NTC open circuit
F. 1
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
Water shortage, temperature difference between flow
F.23
and return NTC too large
F.24 Water shortage, temperature rise too quick
Interruption in the compact thermal module cable har-
F.25
ness
F.27 Incorrect sensing of flame
Appliance does not start: Attempts to ignite during start
F.28
failed
Flame goes off during operation and subsequent ignition
F.29
attempts failed
F.32 Fan speed variation
F.49 eBUS undervoltage
F.61 Gas–valve control defective
F.62 Gas valve shutoff delay
F.63 EEPROM error
F.64 Electronics/NTC fault
F.65 Electronics temperature too high
Flame detector input signal is outside the limits
F.67
(0 or 5 V)
F.70 No valid DSN in display and/or mainboard
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.74 Water pressure sensor signal out of range (too high)
F.75 No pressure rise was detected on turning on the pump
Overheating protection on primary heat exchanger trig-
F.76
gered
condensate pump or feedback of accessorie blocks heat-
F.77
ing
F.78 wrong configuration with accessory
con no communication to mainboard
Table 8.4 Error codes
46
Cause
NTC broken, NTC cable broken, Defective connection at NTC,
Defective connection at electronics
NTC broken, NTC cable broken, Defective connection at NTC,
Defective connection at electronics
NTC defective, short circuit in cable harness, cable/casing shortcut
NTC defective, short circuit in cable harness, cable/casing shortcut
NTC defective, short circuit in cable harness, cable/casing shortcut
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 defec-
tive, pump output too low
Pump blocked or defective, pump output too low, flow and return
NTC interchanged
Pump blocked, insufficient pump output, air in appliance, water
pressure too low
Compact thermal module cable harness defective
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 trans-
former, ignition cable, ignition plug) defective, ionisation current
stopped (cable, electrode), faulty earthing in appliance, electronics
defective
Gas supply temporarily stopped, faulty earthing of appliance
Fan blocked, plug not inserted correctly on fan, hall sensor defec-
tive, fault in cable harness, electronics defective
Short circuit on eBUS, overload on eBUS or two power sources on
eBUS with different 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 maiboard interchanged at same time
and device specific number not adjusted
Flow NTC is defective
Flow and/or return NTC is defective (tolerances too big)
Cable to water pressure sensor is broken or has a short-circuit at
0 V or water pressure sensor defective
Cable to water pressure sensor has a short-circuit at 5 V / 24 V or
internal fault in water pressure sensor
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
Cable or cable connection of fuse in the primary heat exchanger
defective, or primary heat exchanger defective
condensate pump defective or flume flap feedback triggered
link box VR65 connected to combination boiler
connection error display mainboard
Instructions for installation and servicing ecoTEC / 839592_09