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Vaillant Fault Codes New

CodeMessage Possible causeMeasureArticle Page / Link
F.00Interruption: Flow sensorFlow temperature sensor de- ▶ fective or not connectedCheck: Flow temperature sensor, plug, cable harness, PCB.
F.01Interruption: Return sensorReturn temperature sensor de- ▶ fective or not connectedCheck: Return temperature sensor, plug, cable harness, PCB.
F.02Interruption: DHW outlet sensorCylinder temperature sensor for ▶ the shift-load cylinder defective
or not connected
On the shift-load cylinder, check (only in conjunction with F.91): Plug, cable harness, temperature sensor.
F.03 Interruption: Cylinder sensorTemperature sensor for the ▶ shift-load cylinder defective or
not connected
On the shift-load cylinder, check (only in conjunction with F.91): Temperature sensor plug, temperature sensor, PCB plug, cable harness.
F.10Short circuit: Flow sensorFlow temperature sensor de- ▶ fective or has short-circuitedCheck: NTC plug, cable harness, cable/housing, PCB, NTC sensor.
F.11Short circuit: Return
Return temperature sensor de- ▶ fective or has short-circuitedCheck: NTC plug, cable harness, housing, PCB, NTC sensor.
F.12Short circuit: DHW outlet sensorCylinder temperature sensor ▶ defective or has short-circuitedCheck (only in conjunction with F.91): NTC plug, cable har- ness, NTC sensor, PCB.
F.13Short circuit: Cylinder sensorWarm start sensor/cylinder tem- perature sensor defective or not connected1. Check: NTC plug, earth connection, cable harness, NTC sensor, PCB.
2. Check the following on the shift-load cylinder (in conjunction with F.91): NTC plug, earth connection, cable harness, NTC sensor, connection to the PCB.
F.20Safety switch-off: Temper- ature limiterMaximum temperature at the flow/return temperature sensor is too high when the safety cut- out function is operating using the NTCCheck:Flowtemperaturesensor(correctthermalconnection), cable harness, sufficient purging.
F.22 Safety switch-off: Low wa- ter pressureNo/insufficient water in the 1. product or the water pressure is
too low
Check: Plug, cable to heating pump or water pressure sensor, water pressure sensor, heating pump.
2. Activate and purge check programme P.0.
F.23 Safety switch-off: Temp.spread too largeTemperature spread too great. Water circulation too lowCheck:Plug,cabletoheatingpump/waterpressuresensor, air/insufficient water in the heating circuit, flow and return tem- perature sensor inverted, strainer in the hydraulic block, water pressure sensor, heating pump (sufficient circulation, level 2: D.19, D.14, non-return valve). Activate check programme P.0.
F.24 Safety switch-off: Temp. incr. too fastTemperature increase too fastCheck:Plug,cabletotheheatingpump,air/insufficientwater in the heating circuit, internal air vent (function), heating pump (system pressure too low, temperature gradient too great on heating flow, non-return valve). Activate check programme P.0
F.25 Safety switch-off: Flue temp. too highflue gas temperature too highCheck:Plug,safetycut-outplug,cableharness,cabletothe heating pump, internal air vent (function), flue gas route (block- age, adverse wind conditions, flue pipework too long), insuf- ficient water in heating circuit, heating pump, activate check programme P.0.
F.26 Fault: Fuel valve not work- ingGas valve assembly stepper ▶ motor defective or not connec-
Check: Gas valve assembly stepper motor (plug, cable, pas- sage for rinsing, voltage), multiple plug, cable harness.
F.27 Safety switch-off: Flame simulationMonitoring electrode reports an ▶ incorrect flameCheck: Gas pressure at upper test opening, monitoring elec- trode, PCB, gas solenoid valve.
F.28 Start-up failure: Ignit. un- successfulFailure during start-up or igni- tion unsuccessful. Gas pressure monitor or thermal cut-out has been triggered.Check:Gasstopcock,gasflowpressure,gasvalveassembly, air intake pipe (blockage, loosened screw), condensate route (blockage), multiple plug, cable harness, ignition transformer, ignition cable, ignition plug, ignition electrode, monitoring elec- trode, electronics, earthing, CO2 setting.
F.29 Operating failure: Ignit. unsuccessfulGas supply interrupted intermit- ▶ tently. Re-ignition failed.
Check: Flue gas recirculation, condensate route (blockage), earthing, cable to the gas valve assembly and electrode (loose connection).
F.32 Fault: FanFan defective or not connected Check: Plug, cable harness, fan (blockage, function, correct speed), Hall sensor, PCB, flue gas route (blockage).
F.42 Fault: Coding resistor
Coding resistor or gas group ▶
resistor causes a short circuit
Check: Plug, earth connection, cable, output coding resistor (in the cable harness).
F.49 Fault: eBUSUndervoltage on the eBUSCheck: eBUS (overload, two power supplies with different po- larities, short circuit).
F.52 Mass flow sensor not con- nectedMass flow sensor defective or ▶ not connected
Check: Plug, cable harness, mass flow sensor.
F.53 Fault: Mass flow sensorMass flow sensor defectiveCheck:FilterbelowVenturifiltercapwetorblocked,gasflow pressure too low, internal pressure measuring point in the Ven- turi is blocked (do not use any lubricants on the O-ring in the Venturi).
F.54 Fault: Boiler startNo gas inlet pressure or insuffi- cient gas inlet pressure causes faults when the product is star- tedCheck(inconjunctionwithF.28/F.29):Gasstopcock,gasvalve assembly, plug, cable harness.
F.55 Fault: CO sensorAll-gas sensor defective or has ▶ short-circuitedCheck: Plug, cable harness, all-gas sensor, PCB.
F.56 Safety switch-off: CO limit
Safety shutdown after the CO ▶ limit value is exceeded
Check: Gas valve assembly, plug, cable harness. If the fault occurs again after being cleared, the gas valve assembly is defective.
F.57 Fault: Measuring program
Regulation fault caused by cor- ▶ roded ignition electrodeCheck: Ignition electrode, PCB (microcontrol).
F.61 Fault: Fuel valve actuation
The gas valve assembly cannot ▶ be actuatedCheck: Cable harness, plug, gas valve assembly (rinse), PCB.
F.62 Fault: Fuel valve switch-off delayDelayed switch-off sequence for ▶ the gas valve after the flame is extinguishedCheck: Gas valve, surface of the burner (dirt), plug, cable har- ness, PCB.
F.63 Fault: EEPROMEEPROM faultyReplace: PCB.
F.64 Fault: Electronics/sensor
Electronics, safety-relevant ▶
sensor or cable defective
Check: Flow sensor, cable to the sensor, flame recording sensor (e.g. ionisation electrode) for an unstable signal, electronics.
F.65 Fault: Electronics temp.Electronics defective or too hot 1.
due to external influences
Check: PCB.
2. If required, reduce the environmental temperature.
F.67 Fault: Electronics/flameImplausible flame signalCheck: Cable harness, flame monitor, PCB.
F.68 Fault: Flame signal un- stableFlame monitor reports an un- ▶ stable flame signalCheck: Air ratio, gas flow pressure, condensate route (block- age), gas injector, ionisation flow (cable, electrode), flue gas recirculation.
F.70 Fault: Invalid Device Spe- cific Number
Incorrect/missing Device ▶ Specific Number or
incorrect/missing coding resistor
f the display and PCB have been replaced, change the Device Specific Number under D.93.
F.71 Fault: Flow sensorFlow temperature sensor re- ▶ turns implausible valuesCheck: Flow temperature sensor (correct thermal connection).
F.72 Fault: Flow/return sensor
Temperature difference ▶ between flow and return temperature sensor is too greatCheck: Flow temperature sensor/return temperature sensor (function, correct thermal connection).
F.73 Fault: Water press. sensor (signal too weak)Water pressure sensor reports ▶ that the water pressure is too
Check: Water pressure, earth connection, cable, plug, water pressure sensor (short circuit to GDN).
F.74 Fault: Water press. sensor (signal too strong)Water pressure too high1. Drain water
2. Check the water pressure sensor.
F.75 Fault: Pump/ water short- ageInsufficient pressure jump de- tected when starting the pump1. Check: Water pressure sensor, heating pump (blockage), heating circuit (air, sufficient water volume), adjustable by- pass, external expansion vessel (must be connected at the return). Activate check programme P.0.
2. If a low loss header or heating pipes with a diameter greater than 1 1/2 inch are installed, replace the 3/4-inch seal in the heating flow with a screen. If required, install the F.75 service set.
F.77 Fault: Flue non-ret. valve/condens. pumpNo flue non-return flap feed- ▶
back; condensate pump over-
Check: Cable to VR40 accessory, flue non-return flap (wiring, feedback switch), condensate pump, bridge from the surface-
mounted thermostat, 2 in 7 multi-functional module (bridge).
F.78 Interrupt.: DHW outlet sensor on ext. contr.UK link box is connected without the domestic hot water temperature sensor being bridged1. Check: Accessory (configuration/electrical connection).
2. The unit displays a fault, but the unit has not malfunctioned.
F.80 Fault: actoSTOR inlet sensorInlet temperature sensor defect-ive or not connected ▶ Check (only in conjunction with F.91): NTC sensor, plug, cable harness, PCB.
F.81 Fault: cylinder charging pumpCylinder is not fully charged after specified timeCheck(onlyinconjunctionwithF.91):Cylindercharging sensor, cylinder sensor, impeller sensor/limiter, prioritising diverter valve, pump, actoSTOR pump (air), cable harness, secondary heat exchanger (blockage).
F.82 Fault: Ext. current anodeExternal current anode defect-ive or not connectedCheck: Cable harness, external current anode. If the external current ▶ anode is not installed: Plug edge connector X43 with a bridge into the PCB.
F.83 Fault: NTC temp. gradientTemperature difference ▶ between flow and return temperature sensor is too smallCheck: Flow/return temperature sensor (function, correct thermal connection), sufficient water volume.
F.84 Fault: NTC temp. diff. im- plausibleTemperature difference is im-plausible ▶ Check: Flow/return temperature sensor (correct thermal con- nection, sensors are inverted).
F.85 Fault: NTCs fitted incor- rectlyFlow/return temperat- ▶ ure sensors returning incorrect/implausible valuesCheck: Flow/return temperature sensor (correct thermal con- nection).
F.90 Fault: CommunicationCommunication with actoSTOR interrupted1. Check: Plug, check cable harness to the actoSTOR module (PEBus).
2. If the product is to be operated without an actoSTOR: Set D.092=0, if required, plug edge connector X31 into the BMU, if required plug edge connector X1 into the actoSTOR.
F.91 Fault: actoSTOR sensorSensor on the actoSTOR is defective▶ Check: Plug, cable harness, sensor.
F.92 Fault: Incorrect gas type
The coding resistor on the PCB does not match the gas group that is entered1. Check: Coding resistor.
2. Carry out the gas family check again and enter the correct gas group.
F.93 Fault: Check gas routeCombustion quality outside the permitted range Check:Gasinjector(suitableforthegasgroup),fluegasre- circulation, gas group, internal pressure measuring point in the Venturi (blockage). Do not use any lubricants on the O-ring in the Venturi.
F.94 Fault: Vortex and differen- tial pressureSensors return implausible values ▶ Check: Cable harness, plug, sensors.
LED actoSTOR Modul
actoSTOR communication status
actoSTOR communication status: Not connected, Con- nection error, Connection active1. LED on: Communication OK.
2. LED flashing: Communication not OK.
3. LED off: No power supply.
CommunicationfaultCommunicationfaultbetweenthe display and the PCB in the
electronics box
▶ Check:Cable/plugbetweenthedisplayandthePCB.

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