| Code | Message | Possible cause | Measure | Article Page / Link |
|---|---|---|---|---|
| F.00 | Interruption: Flow sensor | Flow temperature sensor de- â–¶ fective or not connected | Check: Flow temperature sensor, plug, cable harness, PCB. | |
| F.01 | Interruption: Return sensor | Return temperature sensor de- â–¶ fective or not connected | Check: Return temperature sensor, plug, cable harness, PCB. | |
| F.02 | Interruption: DHW outlet sensor | Cylinder temperature sensor for â–¶ 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 sensor | Temperature sensor for the â–¶ 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.10 | Short circuit: Flow sensor | Flow temperature sensor de- â–¶ fective or has short-circuited | Check: NTC plug, cable harness, cable/housing, PCB, NTC sensor. | |
| F.11 | Short circuit: Return sensor | Return temperature sensor de- â–¶ fective or has short-circuited | Check: NTC plug, cable harness, housing, PCB, NTC sensor. | |
| F.12 | Short circuit: DHW outlet sensor | Cylinder temperature sensor â–¶ defective or has short-circuited | Check (only in conjunction with F.91): NTC plug, cable har- ness, NTC sensor, PCB. | |
| F.13 | Short circuit: Cylinder sensor | Warm start sensor/cylinder tem- perature sensor defective or not connected | 1. 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.20 | Safety switch-off: Temper- ature limiter | Maximum temperature at the flow/return temperature sensor is too high when the safety cut- out function is operating using the NTC | Check:Flowtemperaturesensor(correctthermalconnection), cable harness, sufficient purging. | |
| F.22 | Safety switch-off: Low wa- ter pressure | No/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 large | Temperature spread too great. Water circulation too low | Check: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 fast | Temperature increase too fast | Check: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 high | flue gas temperature too high | Check: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- ing | Gas valve assembly stepper â–¶ motor defective or not connec- ted | Check: Gas valve assembly stepper motor (plug, cable, pas- sage for rinsing, voltage), multiple plug, cable harness. | |
| F.27 | Safety switch-off: Flame simulation | Monitoring electrode reports an â–¶ incorrect flame | Check: Gas pressure at upper test opening, monitoring elec- trode, PCB, gas solenoid valve. | |
| F.28 | Start-up failure: Ignit. un- successful | Failure 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. unsuccessful | Gas supply interrupted intermit- â–¶ 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: Fan | Fan 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 â–¶ resistor causes a short circuit | Check: Plug, earth connection, cable, output coding resistor (in the cable harness). | ||
| F.49 Fault: eBUS | Undervoltage on the eBUS | Check: eBUS (overload, two power supplies with different po- larities, short circuit). | ||
| F.52 Mass flow sensor not con- nected | Mass flow sensor defective or â–¶ not connected | Check: Plug, cable harness, mass flow sensor. | ||
| F.53 Fault: Mass flow sensor | Mass flow sensor defective | Check: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 start | No gas inlet pressure or insuffi- cient gas inlet pressure causes faults when the product is star- ted | Check(inconjunctionwithF.28/F.29):Gasstopcock,gasvalve assembly, plug, cable harness. | ||
| F.55 Fault: CO sensor | All-gas sensor defective or has â–¶ short-circuited | Check: Plug, cable harness, all-gas sensor, PCB. | ||
| F.56 Safety switch-off: CO limit exceeded | Safety shutdown after the CO â–¶ 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- â–¶ roded ignition electrode | Check: Ignition electrode, PCB (microcontrol). | ||
| F.61 Fault: Fuel valve actuation | The gas valve assembly cannot â–¶ be actuated | Check: Cable harness, plug, gas valve assembly (rinse), PCB. | ||
| F.62 Fault: Fuel valve switch-off delay | Delayed switch-off sequence for â–¶ the gas valve after the flame is extinguished | Check: Gas valve, surface of the burner (dirt), plug, cable har- ness, PCB. | ||
| F.63 Fault: EEPROM | EEPROM faulty | Replace: PCB. | ||
| F.64 Fault: Electronics/sensor | Electronics, safety-relevant â–¶ 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/flame | Implausible flame signal | Check: Cable harness, flame monitor, PCB. | ||
| F.68 Fault: Flame signal un- stable | Flame monitor reports an un- â–¶ stable flame signal | Check: 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 â–¶ 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 sensor | Flow temperature sensor re- â–¶ turns implausible values | Check: Flow temperature sensor (correct thermal connection). | ||
| F.72 Fault: Flow/return sensor | Temperature difference â–¶ between flow and return temperature sensor is too great | Check: Flow temperature sensor/return temperature sensor (function, correct thermal connection). | ||
| F.73 Fault: Water press. sensor (signal too weak) | Water pressure sensor reports â–¶ that the water pressure is too low | 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 high | 1. Drain water 2. Check the water pressure sensor. | ||
| F.75 Fault: Pump/ water short- age | Insufficient pressure jump de- tected when starting the pump | 1. 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. pump | No flue non-return flap feed- â–¶ back; condensate pump over- flow | 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 bridged | 1. Check: Accessory (configuration/electrical connection). 2. The unit displays a fault, but the unit has not malfunctioned. | ||
| F.80 Fault: actoSTOR inlet sensor | Inlet temperature sensor defect-ive or not connected | â–¶ Check (only in conjunction with F.91): NTC sensor, plug, cable harness, PCB. | ||
| F.81 Fault: cylinder charging pump | Cylinder is not fully charged after specified time | Check(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 anode | External current anode defect-ive or not connected | Check: Cable harness, external current anode. If the external current â–¶ anode is not installed: Plug edge connector X43 with a bridge into the PCB. | ||
| F.83 Fault: NTC temp. gradient | Temperature difference â–¶ between flow and return temperature sensor is too small | Check: Flow/return temperature sensor (function, correct thermal connection), sufficient water volume. | ||
| F.84 Fault: NTC temp. diff. im- plausible | Temperature difference is im-plausible | â–¶ Check: Flow/return temperature sensor (correct thermal con- nection, sensors are inverted). | ||
| F.85 Fault: NTCs fitted incor- rectly | Flow/return temperat- â–¶ ure sensors returning incorrect/implausible values | Check: Flow/return temperature sensor (correct thermal con- nection). | ||
| F.90 Fault: Communication | Communication with actoSTOR interrupted | 1. 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 sensor | Sensor on the actoSTOR is defective | â–¶ 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 entered | 1. Check: Coding resistor. 2. Carry out the gas family check again and enter the correct gas group. | ||
| F.93 Fault: Check gas route | Combustion 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 pressure | Sensors return implausible values | â–¶ Check: Cable harness, plug, sensors. | ||
| LED actoSTOR Modul actoSTOR communication status | actoSTOR communication status: Not connected, Con- nection error, Connection active | 1. LED on: Communication OK. 2. LED flashing: Communication not OK. 3. LED off: No power supply. | ||
| Communicationfault | Communicationfaultbetweenthe display and the PCB in the electronics box | â–¶ Check:Cable/plugbetweenthedisplayandthePCB. |
Vaillant Fault Codes New
Disclaimer: Information on this website is provided for informational purpose therefore we cannot accept liability for subsequent problems. All repair tasks should be carried out by qualified trades people. We may also receive commission payments when you are taken to external websites and complete purchases from third party sellers, once you leave our site, we cannot be held liable for your purchases.