Vaillant ECOTEC PLUS VU 80, Installation And Maintenance Instructions Manual

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Troubleshooting
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ecoTEC plus installation and maintenance instructions 0020134823_01
14
14.2.9 Overview of fault codes
Code Meaning Cause
F.00 Flow temperature sensor interruption NTC plug not plugged in or has come loose, multiple plug on the PCB
not plugged in correctly, interruption in cable harness, NTC defective
F.01 Return temperature sensor interruption NTC plug not plugged in or has come loose, multiple plug on the PCB
not plugged in correctly, interruption in cable harness, NTC defective
F.10 Short circuit, flow sensor Sensor plug has a short to the casing, short-circuit in cable harness,
sensor faulty
F.11 Short circuit, return sensor Sensor plug has a short to the casing, short-circuit in cable harness,
sensor faulty
F.20 Temperature safety switch-off Earth connection of cable harness to boiler not correct, when the
burner cover safety cut-out triggers: burner door seal or burner iso-
lation defective.
When the flow safety cut-out triggers: pump fault
F.22 Low water pressure safety switch-off No or too little water in the boiler, water pressure sensor defective,
cable to pump or water pressure sensor loose/not connected/
defective
F.23 Safety switch-off: Temperature difference too great Pump blocked, insufficient pump output, air in boiler, flow and return
NTC interchanged
F.24 Safety switch-off: Temperature rise too fast Pump blocked, poor pump performance, air in boiler, system pressure
too low, non-return valve blocked/incorrectly installed
F.25 Safety switch-off: Flue gas temperature too high Break in plug connection for optional flue gas safety temperature
limiter (safety cut-out), break in cable harness
F.27 Safety switch-off: Flame simulation Moisture on the electronics, electronics (flame monitor) defective,
gas solenoid valve leaking
F.28 Failure during start-up: Ignition unsuccessful Gas meter defective or gas pressure monitor has been triggered, air
in gas, gas connection pressure (gas flow pressure) too low,
Thermal isolator device (TAE) has been triggered, condensate duct
blocked, incorrect gas restrictor, incorrect ET gas valve, failure at gas
valve, multiple plug on PCB incorrectly plugged in, break in cable har-
ness, ignition system (ignition transformer, ignition cable, ignition
plug, ignition electrode) defective, ionisation current interrupted
(cable, electrode), incorrect earthing of boiler, electronics defective
F.29 Failure during operation: Re-ignition unsuccessful Gas supply temporarily stopped, flue gas recirculation, condensate
duct blocked, faulty earthing of boiler, ignition transformer has spark
failure
F.32 Fan fault Plug on fan not correctly plugged in, multiple plug on PCB not cor-
rectly plugged in, break in cable harness, fan blocked, Hall sensor
defective, electronics defective
F.34 Safety switch-off: pressure monitoring Flue gas pressure cartridge: cable break, blocked flue gas route
Water pressure switch: hydraulic leak, air in heating circuit
F.35 Flue pipe fault Flue pipe blocked
F.49 eBUS fault Short circuit on eBUS, eBUS overload or two power supplies with dif-
ferent polarities on the eBUS
F.61 Fault: Gas valve regulation - Short circuit/short to earth in cable harness for the gas valve
- Gas valve defective (coils shorted to earth)
- Electronics defective
F.62 Fault: Gas valve switch-off delay - Delayed shutdown of gas valve
- Delayed extinguishing of flame signal
- Gas valve leaking
- Electronics defective
F.63 EEPROM fault Electronics defective
F.64 Electronics/sensor fault Flow or return NTC short circuited, electronics defective
F.65 Electronic temperature fault Electronics overheating due to external influences, electronics
defective
F.67 Electronics/flame fault Implausible flame signal, electronics defective
F.70 Invalid device code Spare parts case: Display and PCB replaced at the same time and
unit variant not reset
14.3 Fault codes