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

13.2.8 Overview of fault codes

Code Meaning
F.00 Flow temperature sensor interruption
F.01 Return temperature sensor interruption
F.02 Interruption cylinder charging sensor actoSTOR
(NTC) only in combination with F.91
F.03 Interruption cylinder sensor actoSTOR (NTC)
only in combination with F.91
F.10 Flow NTC short circuit
F.11 Return NTC short circuit
F.12 Short circuit at cylinder charging sensor (NTC)
only in combination with F.91
F.13 VU-/VUW boiler: Short circuit warm start sensor/
cylinder sensor
VUW boiler with actoSTOR: Short circuit cylinder
sensor (NTC) only in combination with F.91
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.35 Air/flue gas duct fault
F.42 Coding resistance fault (possible in combination
with F.70)
13.2 Fault codes
Installation and maintenance instructions ecoTEC plus 0020116700_01
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, NTC cable defective, defective plug connection on NTC,
defective plug connection on actoSTOR electronics
NTC defective, NTC cable defective, defective plug connection on NTC,
defective plug connection on actoSTOR electronics
NTC defective, short circuit in cable harness, cable/casing
NTC defective, short circuit in cable harness, cable/casing
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 or low water pressure in the boiler, water pressure 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
Air/flue gas duct blocked
Short circuit/interruption in coding resistance output range (in cable
harness at heat exchanger) or gas group resistor (on PCB)
Troubleshooting 13
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