Vaillant ecoFIT pure Installation And Maintenance Instructions Manual page 33

Fault code Meaning
F.20 Safety switch-off: Overheating temperat-
ure reached
F.22 Safety switch-off: Low water pressure in
the boiler
F.23 Safety switch-off: Temperature difference
too great (NTC1/NTC2)
F.24 Safety switch-off: Temperature rise too
fast
F.25 Safety switch-off: Flue gas temperature
too high
F.27 Safety switch-off: Fault in flame detection
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 control system
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 controller
F.83 Fault: Dry fire
0020230533_01 ecoFIT pure Installation and maintenance instructions
Possible cause
Incorrect earth connection between cable harness and product, flow or return
NTC defective (loose connection), black discharge 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 (STB), break in
cable harness
Moisture on the electronics, electronics (flame monitor) defective, gas solen-
oid valve leaking
Gas meter defective or gas pressure monitor has triggered, air in gas, gas
flow pressure too low, thermal isolator device (TAE) has triggered, incorrect
gas restrictor, incorrect spare gas valve, fault on the gas valve, multiple plug
on PCB incorrectly plugged in, break in cable harness, ignition system (ig-
nition transformer, ignition cable, ignition plug, ignition electrode) defective,
ionisation current interrupted (cable, electrode), incorrect earthing of product,
electronics defective
Gas supply temporarily stopped, flue gas recirculation, incorrect earthing of
product, ignition transformer has spark failure
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 earth in cable harness for the gas valve, gas valve
defective (coils shorted to earth), electronics defective
Delayed switch-off of gas valve, delayed extinguishing of flame signal, gas
valve 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 re-
strictor, ionisation flow interruption (cable, electrode)
Display and PCB replaced at same time and Device Specific Number not
reset, wrong or missing output range coding resistance
Flow temperature sensor signalling constant value: Flow temperature sensor
incorrectly positioned on supply 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 line 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 feedback
No response, flue non-return flap defective
UK link box is connected, but hot water NTC not bridged
When the burner starts, the temperature change registered at the flow or
return temperature sensor is non-existent or too small: Insufficient water
in the product, the flow or return temperature sensor is not in the correct
position on the pipe
Appendix
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