Vaillant auroCOMPACT VSC S/4 Series Installation And Maintenance Instructions Manual page 53

Code Meaning
F.27 Safety switch-off: Flame simulation
F.28 Failure during start-up: Ignition unsuccessful
F.29 Failure during operation: Re-ignition unsuccess-
ful
F.32 Fan fault
F.35 Lack of air in combustion unit
F.42 Coding resistance fault (possible in combination
with F.70)
F.47 Detachment of hot water sensor in cylinder outlet
(flow rate detection)
F.48 Hot water sensor short circuit at cylinder outlet
(flow rate detection)
F.49 Fault: eBUS
F.52 Mass flow sensor connection fault
F.53 Mass flow sensor fault
F.54 Gas pressure fault (in combination with
F.28/F.29)
F.56 Fault: Mass flow sensor regulation
F.57 Fault during comfort safety mode
F.61 Gas valve control system fault
F.62 Gas valve fault, switch-off delay
F.63 Fault: EEPROM
F.64 Fault: Electronics/NTC
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.68 Fault: Unstable flame signal
F.70 Invalid device specific number (DSN)
F.71 Flow NTC fault
F.72 Flow/return NTC fault
F.73 Water pressure sensor signal in the wrong range
(too low)
0020181589_04 auroCOMPACT Installation and maintenance instructions
Cause
Moisture on the electronics, electronics (flame monitor) defective, gas
solenoid 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,
condensate duct blocked, incorrect gas restrictor, incorrect spare part
gas valve, fault on the gas valve, multiple plug on PCB incorrectly
plugged in, break in cable harness, ignition system (ignition 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, condensate duct
blocked, defective 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,
electronics defective
Fan speed not correct, air supply or smoke outlet blocked, plug not
correctly connected to fan, multiple plug on PCB not correctly connected,
break in cable harness, fan blocked, Hall sensor defective, electronics
defective
Short circuit/interruption in output range coding resistance (in cable
harness at heat exchanger) or gas group resistor (on PCB)
NTC defective, NTC cable defective, defective plug connection on NTC
NTC defective, short circuit in cable harness, cable/casing
Short circuit on eBUS, eBUS overload or two power supplies with differ-
ent polarities on the eBUS
Mass flow sensor not connected/disconnected, plug not connected or
incorrectly connected
Gas flow pressure too low, filter under Venturi filter cap wet or blocked,
mass flow sensor defective, internal pressure measuring point in Venturi
blocked (do not use lubricant on Venturi O-ring.)
No or insufficient gas inlet pressure, gas isolator cock closed
Gas valve defective, cable harness to gas valve defective
Ignition electrode highly corroded
–
Short circuit/short to earth in cable harness for the gas valve
–
Gas valve defective (coils shorted to earth)
–
Electronics defective
–
Delayed shutdown 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, condensate
duct blocked, incorrect gas restrictor, ionisation flow interruption (cable,
electrode), flue gas recirculation, condensate duct
If spare parts fitted: Display and PCB replaced at same time and DSN
not reset, incorrect or missing output range coding resistance
Flow temperature sensor signalling constant value:
–
Flow temperature sensor incorrectly positioned at supply pipe
–
Flow temperature sensor defective
Flow/return NTC temperature difference too great → flow and/or return
temperature 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
Appendix
53