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boiler service, boiler repair, emergency repair
Vaillant ecoTECpro 30H combi Boiler Fault Codes
| Message | Possible Cause | Measure |
| F00 Interruption: Flow sensor | Flow temperature sensor defective or not connected | ▶ Check: Flow temperature sensor, plug, cable harness, PCB. |
| F01 Interruption: Return sensor | Return temperature sensor defective or not connected | ▶ Check: Return temperature sensor, plug, cable harness, PCB. |
| F10 Short circuit: Flow sensor | Flow temperature sensor defective or has short-circuited | ▶ Check: NTC plug, cable harness, cable/housing, PCB, NTC sensor. |
| F11 Short circuit: Return sensor | Return temperature sensor defective or has short-circuited | ▶ Check: NTC plug, cable harness, housing, PCB, NTC sensor. |
| F20 Safety switch-off: Temperature limiter | Maximum temperature at the flow/return temperature sensor is too high when the safety cut-out function is operating using the NTC | ▶ Check: Flow temperature sensor (correct thermal connection), cable harness, sufficient purging. |
| F22 Safety switch-off: Low water pressure | No/insufficient water in the product or the water pressure is too low |
1. Check: Plug, cable to heating pump or water pressure sensor, water pressure sensor, heating pump. 2. Activate and purge check programme P.0. |
| F23 Safety switch-off: Temp.spread too large | Temperature spread too great. Water circulation too low | ▶ Check: Plug, cable to heating pump/water pressure sensor, air/insufficient water in the heating circuit, flow and return temperature 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. |
| F24 Safety switch-off: Temp. incr. too fast | Temperature increase too fast | ▶ Check: Plug, cable to the heating pump, air/insufficient water 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. |
| F25 Safety switch-off: Flue temp. too high | flue gas temperature too high | ▶ Check: Plug, safety cut-out plug, cable harness, cable to the heating pump, internal air vent (function), flue gas route (blockage, adverse wind conditions, flue pipework too long), insufficient water in heating circuit, heating pump, activate check programme P.0. |
| F26 Fault: Fuel valve not working | Gas valve assembly stepper motor defective or not connected | ▶ Check: Gas valve assembly stepper motor (plug, cable, passage for rinsing, voltage), multiple plug, cable harness. |
| F27 Safety switch-off: Flame simulation | Monitoring electrode reports an incorrect flame | ▶ Check: Gas pressure at upper test opening, monitoring electrode, PCB, gas solenoid valve. |
| F28 Start-up failure: Ignit. unsuccessful | Failure during start-up or ignition unsuccessful. Gas pressure monitor or thermal cut-out has been triggered. | ▶ Check: Gas stopcock, gas flow pressure, gas valve assembly, air intake pipe (blockage, loosened screw), condensate route (blockage), multiple plug, cable harness, ignition transformer, ignition cable, ignition plug, ignition electrode, monitoring electrode, electronics, earthing, CO₂ setting. |
| F29 Operating failure: Ignit. unsuccessful | Gas supply interrupted intermittently. Re-ignition failed. | ▶ Check: Flue gas recirculation, condensate route (blockage), earthing, cable to the gas valve assembly and electrode (loose connection). |
| F32 Fault: Fan | Fan defective or not connected | ▶ Check: Plug, cable harness, fan (blockage, function, correct speed), Hall sensor, PCB, flue gas route (blockage) |
| F49 Fault: eBUS | Undervoltage on the eBUS | ▶ Check: eBUS (overload, two power supplies with different polarities, short circuit). |
| F61 Fault: Fuel valve actuation | The gas valve assembly cannot be actuated | ▶ Check: Cable harness, plug, gas valve assembly (rinse), PCB. |
| F62 Fault: Fuel valve switch-off delay | Delayed switch-off sequence for the gas valve after the flame is extinguished | ▶ Check: Gas valve, surface of the burner (dirt), plug, cable harness, PCB. |
| F63 Fault: EEPROM | EEPROM faulty | ▶ Replace: PCB. |
| F64 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. |
| F65 Fault: Electronics temp. | Electronics defective or too hot due to external influences |
1. Check: PCB. 2. If required, reduce the environmental temperature. |
| F67 Fault: Electronics/flame | Implausible flame signal | ▶ Check: Cable harness, flame monitor, PCB. |
| F68 Fault: Flame signal unstable | Flame monitor reports an unstable flame signal | ▶ Check: Air ratio, gas flow pressure, condensate route (blockage), gas injector, ionisation flow (cable, electrode), flue gas recirculation. |
| F70 Fault: Invalid Device Specific Number | Incorrect/missing Device Specific Number or incorrect/missing coding resistor | ▶ If the display and PCB have been replaced, change the Device Specific Number under D.93. |
| F71 Fault: Flow sensor | Flow temperature sensor returns implausible values | ▶ Check: Flow temperature sensor (correct thermal connection). |
| F72 Fault: Flow/return sensor | Temperature difference between flow and return temperature sensor is too great | ▶ Check: Flow temperature sensor/return temperature sensor (function, correct thermal connection). |
| F73 Fault: Water press. sensor (signal too weak) | Water pressure sensor reports that the water pressure is too low | ▶ Check: Water pressure, earth connection, cable, plug, water pressure sensor (short circuit to GDN). |
| F74 Fault: Water press. sensor (signal too strong) | Water pressure too high |
1. Drain water. 2. Check the water pressure sensor. |
| F75 Fault: Pump/ water shortage | Insufficient pressure jump detected when starting the pump |
1. Check: Water pressure sensor, heating pump (blockage), heating circuit (air, sufficient water volume), adjustable bypass, 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 F75 service set. |
| F77 Fault: Flue non-ret. valve/condens. pump | No flue non-return flap feedback; condensate pump overflow | ▶ 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). |
| F78 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. |
| F83 Fault: NTC temp. gradient | Temperature difference between flow and return temperature sensor is too small | ▶ Check: Flow/return temperature sensor (function, correct thermal connection), sufficient water volume. |
| F84 Fault: NTC temp. diff. implausible | Temperature difference is implausible | ▶ Check: Flow/return temperature sensor (correct thermal connection, sensors are inverted). |
| F85 Fault: NTCs fitted incorrectly | Flow/return temperature sensors returning incorrect/implausible values | ▶ Check: Flow/return temperature sensor (correct thermal connection). |
| Communication fault | Communication fault between the display and the PCB in the electronics box | ▶ Check: Cable/plug between the display and the PCB. |