Overview Of Fault Codes - Vaillant ecoTEC VU Installation And Maintenance Instructions Manual

13 Troubleshooting

13.2.9 Overview of fault codes

Code Meaning
F.00 Flow temperature sensor interruption
F.01 Return temperature sensor interruption
F.10 Flow NTC short circuit
F.11 Return NTC short circuit
F.20 Safety switch-off: temperature limiter
F.22 Safety switch-off: low water pressure
F.23 Safety switch-off: Temperature difference too great Pump blocked, insufficient pump output, air in boiler, flow and return
F.24 Safety switch-off: Temperature rise too fast
F.25 Safety switch-off: Flue gas temperature too high
F.26 Fault: Gas valve without function
F.27 Safety switch-off: Flame simulation
F.28 Failure during start-up: ignition unsuccessful
F.29 Failure during operation: Re-ignition unsuccessful
F.32 Fan fault
F.49 eBUS fault
F.61 Fault: Gas valve regulation
F.62 Fault: Gas valve switch-off delay
F.63 EEPROM error
F.64 Electronics/NTC fault
F.65 Electronic temperature fault
F.67 Electronics/flame fault
13.2 Fault codes
62
Cause
NTC plug not plugged in or has come loose, multiple plug on the PCB
not plugged in correctly, interruption in cable harness, NTC defective
NTC plug not plugged in or has come loose, multiple plug on the PCB
not plugged in correctly, interruption in cable harness, NTC defective
NTC defective, short circuit in cable harness, cable/casing
NTC defective, short circuit in cable harness, cable/casing
Incorrect earth connection between cable harness and boiler, flow or
return NTC defective (loose connection), black discharge via ignition
cable, ignition plug or ignition electrode
No water pressure, or water pressure is too low in the boiler, water pres-
sure sensor defective, cable to pump or water pressure sensor loose/not
connected/defective
NTC interchanged
Pump blocked, poor pump performance, air in boiler, system pressure
too low, non-return valve blocks/incorrectly installed
Break in plug connection for optional flue gas safety thermostat (STB),
break in cable harness
Gas valve stepper motor not connected, multiple plug on the PCB not
plugged in correctly, interruption in cable harness, gas valve stepper
motor defective, electronics defective
Moisture on the electronics, electronics (flame monitor) defective, gas
solenoid valve leaking
Gas meter defective or gas pressure regulator has triggered, air in gas,
gas flow pressure too low, thermal isolator device (TAE) has triggered,
condensate duct blocked, incorrect gas restrictor, incorrect ET 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 boiler, electronics defective
Gas supply temporarily stopped, flue gas recirculation, condensate duct
blocked, faulty earthing of boiler, ignition transformer has spark failure
Plug at fan not correctly plugged in, multiple plug on PCB not correctly
plugged in, break in cable harness, fan blocked, Hall sensor defective,
electronics defective
Short circuit on eBUS, eBUS overload or two power supplies with differ-
ent 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 shutdown of gas valve
- Delayed extinguishing of flame signal
- Gas valve leaking
- Electronics defective
Electronics defective
Supply or return NTC short circuited, electronics defective
Electronics overheating due to external influences, electronics defective
Implausible flame signal, electronics defective
Installation and maintenance instructions ecoTEC 0020173113_01