Vaillant ecoFIT pure Series Installation And Maintenance Instructions Manual page 47

Fault code Meaning
F.12 and Short circuit: Cylinder temperature
F.91 sensor
F.13 Short circuit: Domestic hot water cylinder
temperature sensor
F.20 Safety shutdown: Overheating temperat-
ure reached
F.22 Safety shutdown: Water deficiency in the
boiler
F.23 Safety shutdown: Temperature spread
too great (NTC1/NTC2)
F.24 Safety shutdown: Temperature rise too
fast
F.25 Safety shutdown: Flue gas temperature
too high
F.27 Safety shutdown: Fault in flame detec-
tion
F.28 Fault: Ignition unsuccessful when starting
up
F.29 Fault: Flame loss
F.32 Fan frost protection function active: Fan
speed outside the tolerance values
F.49 eBUS fault: Voltage too low
F.61 Fault: Gas valve assembly control
F.62 Fault: Gas valve switch-off control
F.63 Fault: EEPROM
F.64 Fault: Electronics/sensor/analogue-to-
digital converter
F.65 Fault: Electronics temperature too high
F.67 Value sent back by ASIC is incorrect
(flame signal)
F.68 Fault: Unstable flame (analogue input)
F.70 Invalid product code (DSN)
F.71 Fault: Flow/return temperature sensor
F.72 Fault: Deviation in the water pressure
sensor/return temperature sensor
F.73 Fault: Water pressure sensor not con-
nected or has short-circuited
F.74 Fault: Electrical problem in the water
pressure sensor
F.75 Fault: Pressure sensor
F.76 The safety cut-out in the primary heat
exchanger is defective
F.77 Fault: Condensate or smoke
F.78 Interruption to DHW outlet sensor at
external control
0020230533_06 ecoFIT pure Installation and maintenance instructions
Possible cause
NTC sensor defective, short circuit in the cable harness, cable/housing
NTC sensor defective, short circuit in the cable harness, cable/housing
Incorrect earth connection between cable harness and product, flow or return
NTC defective (loose connection), stray spark via ignition cable, ignition plug
or ignition electrode
No or insufficient water in the product, water pressure sensor de-
fective, cable to the pump or to the water pressure sensor loose/not
connected/defective
Pump blocked, insufficient pump output, air in product, flow and return NTC
sensors connected the wrong way round
Pump blocked, insufficient pump output, air in product, system pressure too
low, non-return valve blocked/incorrectly installed
Break in plug connection for optional flue gas safety cut-out (SCO), break in
cable harness
Moisture on the electronics, electronics (flame monitor) defective, gas solen-
oid valve leaking
Gas meter defective or gas pressure switch has triggered, air in gas, gas
flow pressure too low, thermal cut-out has triggered, incorrect gas injector,
incorrect spare gas valve assembly, fault on the gas valve assembly, mul-
tiple plug on PCB incorrectly plugged in, break in cable harness, ignition sys-
tem (ignition transformer, ignition cable, ignition plug, ignition electrode) de-
fective, ionisation flow interrupted (cable, electrode), incorrect earthing of
product, electronics defective
Condensate siphon blocked
Gas supply temporarily stopped, flue gas recirculation, incorrect earthing of
product, ignition transformer has spark failure
Condensate siphon blocked
Plug on fan not correctly plugged in, multiple plug on PCB not correctly
plugged in, break in cable harness, fan blocked, Hall sensor defective, elec-
tronics defective
Short circuit on eBUS, eBUS overload or two power supplies with different
polarities on the eBUS
Short circuit/short-to-ground in cable harness to gas valve assembly, gas
valve assembly defective (coils shorted to earth), electronics defective
Delayed switch-off of gas valve assembly, delayed extinguishing of flame
signal, gas valve assembly leaking, electronics defective
Electronics defective
Flow or return NTC short circuited, electronics defective
Electronics overheating due to external influences, electronics defective
Implausible flame signal, electronics defective
Air in gas, gas flow pressure too low, incorrect air ratio, incorrect gas in-
jector, ionisation flow interruption (cable, electrode)
Display and PCB replaced at same time and Device Specific Number not
reset, wrong or missing output coding resistor
Flow temperature sensor signalling constant value: Flow temperature sensor
incorrectly positioned on flow pipe, flow temperature sensor defective
Flow/return NTC temperature difference too great → flow and/or return tem-
perature sensor defective
Interruption/short circuit of water pressure sensor, interruption/short circuit
to GND in supply pipe to water pressure sensor or water pressure sensor
defective
Line to water pressure sensor has a short circuit to 5 V/24 V or internal fault
in the water pressure sensor
Pressure switch defective
Safety cut-out feedback does not match the gas valve assembly feedback
No response, flue non-return flap defective
UK link box is connected, but domestic hot water NTC not bridged
47