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Vaillant boiler error codes

If you’re currently experiencing problems with your boiler, or a fault code has appeared on your boiler’s control panel, we’re here to help you find out what the error code means.

You can click the links below to find your boiler model.

Vaillant combination boiler error codes

Vaillant system boilers

Vaillant regular boilers

Vaillant combination boiler error codes

 

Vaillant ecoTec Pro combi boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec Pro boiler installed:

Message Possible cause
F.00 Interruption: Flow sensor Flow temperature sensor defective or not connected
F.01 Interruption: Return sensor Return temperature sensor defective or not connected
F.10 Short circuit: Flow sensor Flow temperature sensor defective or has short-circuited
F.11 Short circuit: Return sensor Return temperature sensor defective or has short-circuited
F.20 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
F.22 Safety switch-off: Low water pressure No/insufficient water in the product or the water pressure is too low
F.23 Safety switch-off: Temp. spread too large Temperature spread too great. Water circulation too low
F.24 Safety switch-off: Temp. incr. too fast Temperature increase too fast
F.25 Safety switch-off: Flue temp. too high Flue gas temperature too high
F.26 Fault: Fuel valve not working Gas valve assembly stepper motor defective or not connected
F.27 Safety switch-off: Flame simulation Monitoring electrode reports an incorrect flame
F.28 Start-up failure: Ignit. unsuccessful Failure during start-up or ignition unsuccessful. Gas pressure monitor or thermal cut-out has been triggered.
F.29 Operating failure: Ignit. unsuccessful Gas supply interrupted intermittently. Re-ignition failed.
F.32 Fault: Fan Fan defective or not connected
F.49 Fault: eBUS Undervoltage on the eBUS
F.61 Fault: Fuel valve actuation The gas valve assembly cannot be actuated
F.62 Fault: Fuel valve switch off delay Delayed switch-off sequence for the gas valve after the flame is extinguished
F.63 Fault: EPROM EEPROM faulty
F.64 Fault: Electronics/sensor Electronics, safety-relevant sensor or cable defective
F.65 Fault: Electronics temp. Electronics defective or too hot due to external influences
F.67 Fault: Electronics/flame Implausible flame signal
F.68 Fault: Flame signal un stable Flame monitor reports an un stable flame signal
F.70 Fault: Invalid Device Specific Number Incorrect/missing Device Specific Number or incorrect/missing coding resistor
F.71 Fault: Flow sensor Flow temperature sensor re turns implausible values
F.72 Fault: Flow/return sensor Temperature difference between flow and return temperature sensor is too great
F.73 Fault: Water press. sensor (signal too weak) Water pressure sensor reports that the water pressure is too low
F.74 Fault: Water press. sensor (signal too strong) Water pressure too high
F.75 Fault: Pump/ water shortage Insufficient pressure jump de tected when starting the pump
F.77 Fault: Flue non-ret. valve/condens. pump No flue non-return flap feed back; condensate pump over flow
F.78 Interrupt.: DHW outlet sensor on ext. contr. UK link box is connected without the domestic hot water temperature sensor being bridged
F.83 Fault: NTC temp. gradient Temperature difference between flow and return temperature sensor is too small
F.84 Fault: NTC temp. diff. implausible Temperature difference is im plausible
F.85 Fault: NTCs fitted incorrectly Flow/return temperature sensors returning incorrect/implausible values
Communication fault Communication fault between the display and the PCB in the electronics box

 

Vaillant ecoTec Plus combi boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec Plus boiler installed:

Message Possible cause
F.00 Interruption: Flow sensor Flow temperature sensor de- fective or not connected
F.01 Interruption: Return sensor Return temperature sensor de- fective or not connected
F.02 Interruption: DHW outlet sensor Cylinder temperature sensor for the shift-load cylinder defective or not connected
F.03 Interruption: Cylinder sensor Temperature sensor for the shift-load cylinder defective or not connected
F.10 Short circuit: Flow sensor Flow temperature sensor de- fective or has short-circuited
F.11 Short circuit: Return sensor Return temperature sensor de- fective or has short-circuited
F.12 Short circuit: DHW outlet sensor Cylinder temperature sensor defective or has short-circuited
F.13 Short circuit: Cylinder sensor Warm start sensor/cylinder tem- perature sensor defective or not connected
F.20 Safety switch-off: Tem- perature limiter Maximum temperature at the flow/return temperature sensor is too high when the safety cut- out function is operating using the NTC
F.22 Safety switch-off: Low water pressure No/insufficient water in the product or the water pressure is too low
F.23 Safety switch-off: Temp.spread too large Temperature spread too great. Water circulation too low
F.24 Safety switch-off: Temp. incr. too fast Temperature increase too fast
F.25 Safety switch-off: Flue temp. too high flue gas temperature too high
F.26 Fault: Fuel valve not working Gas valve assembly stepper motor defective or not connec- ted
F.27 Safety switch-off: Flame simulation Monitoring electrode reports an incorrect flame
F.28 Start-up failure: Ignit. unsuccessful Failure during start-up or igni- tion unsuccessful. Gas pressure monitor or thermal cut-out has been triggered.
F.29 Operating failure: Ignit. unsuccessful Gas supply interrupted intermit- tently. Re-ignition failed.
F.32 Fault: Fan Fan defective or not connected
F.42 Fault: Coding resistor Coding resistor or gas group resistor causes a short circuit
F.49 Fault: eBUS Undervoltage on the eBUS
F.52 Mass flow sensor not connected Mass flow sensor defective or not connected
F.53 Fault: Mass flow sensor Mass flow sensor defective
F.54 Fault: Boiler start No gas inlet pressure or insuffi- cient gas inlet pressure causes faults when the product is star- ted
F.55 Fault: CO sensor All-gas sensor defective or has short-circuited
F.56 Safety switch-off: CO limit exceeded Safety shutdown after the CO limit value is exceeded
F.57 Fault: Measuring pro- gram Regulation fault caused by cor- roded ignition electrode
F.61 Fault: Fuel valve actu- ation The gas valve assembly cannot be actuated
F.62 Fault: Fuel valve switch- off delay Delayed switch-off sequence for the gas valve after the flame is extinguished
F.63 Fault: EEPROM EEPROM faulty
F.64 Fault: Electronics/sensor Electronics, safety-relevant sensor or cable defective
F.65 Fault: Electronics temp. Electronics defective or too hot due to external influences
F.67 Fault: Electronics/flame Implausible flame signal
F.68 Fault: Flame signal un- stable Flame monitor reports an un- stable flame signal
F.70 Fault: Invalid Device Specific Number Incorrect/missing Device Specific Number or incorrect/missing coding resistor
F.71 Fault: Flow sensor Flow temperature sensor re- turns implausible values
F.72 Fault: Flow/return sensor Temperature difference between flow and return temperature sensor is too great
F.73 Fault: Water press. sensor (signal too weak) Water pressure sensor reports that the water pressure is too low
F.74 Fault: Water press. sensor (signal too strong) Water pressure too high
F.75 Fault: Pump/ water shortage Insufficient pressure jump de- tected when starting the pump
F.77 Fault: Flue non-ret. valve/condens. pump No flue non-return flap feed- back; condensate pump over- flow
F.78 Interrupt.: DHW outlet sensor on ext. contr. UK link box is connected without the domestic hot water temperature sensor being bridged
F.80 Fault: actoSTOR inlet sensor Inlet temperature sensor defect- ive or not connected
F.81 Fault: cylinder charging pump Cylinder is not fully charged after specified time
F.82 Fault: Ext. current anode External current anode defect- ive or not connected
F.83 Fault: NTC temp. gradi- ent Temperature difference between flow and return temperature sensor is too small
F.84 Fault: NTC temp. diff. implausible Temperature difference is im- plausible
F.85 Fault: NTCs fitted incor- rectly Flow/return temperat- ure sensors returning incorrect/implausible values
F.90 Fault: Communication Communication with actoSTOR interrupted
F.91 Fault: actoSTOR sensor Sensor on the actoSTOR is defective
F.92 Fault: Incorrect gas type The coding resistor on the PCB does not match the gas group that is entered
F.93 Fault: Check gas route Combustion quality outside the permitted range
F.94 Fault: Vortex and differen- tial pressure Sensors return implausible val- ues.
LED actoSTOR Modul actoSTOR communication status actoSTOR communication status: Not connected, Con- nection error, Connection active
Communication fault Communication fault between the display and the PCB in the electronics box

 

Vaillant ecoFit Pure combi boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoFit Pure boiler installed:

Fault code Meaning
F.00 Fault: Flow temperature sensor
F.01 Fault: Return temperature sensor
F.10 Short circuit: Flow temperature sensor
F.11 Short circuit: Return temperature sensor
F.12 and F.91 Short circuit: Cylinder temperature sensor
F.13 Short circuit: Domestic hot water cylinder temperature sensor
F.20 Safety switch-off: Overheating temperat- ure reached
F.22 Safety switch-off: Low water pressure in the boiler
F.23 Safety switch-off: Temperature difference too great (NTC1/NTC2)
F.24 Safety switch-off: Temperature rise too fast
F.25 Safety switch-off: Flue gas temperature too high
F.27 Safety switch-off: Fault in flame detection
F.28 Fault: Ignition unsuccessful when starting up
F.29 Fault: Flame loss
F.32 Fan frost protection function active: Fan speed outside the tolerance values
F.49 eBUS fault: Voltage too low
F.61 Fault: Gas valve control system
F.62 Fault: Gas valve switch-off control
F.63 Fault: EEPROM
F.64 Fault: Electronics/sensor/analogue-to- digital converter
F.65 Fault: Electronics temperature too high
F.67 Value sent back by ASIC is incorrect (flame signal)
F.68 Fault: Unstable flame (analogue input)
F.70 Invalid product code (DSN)
F.71 Fault: Flow/return temperature sensor
F.72 Fault: Deviation in the water pressure sensor/return temperature sensor
F.73 Fault: Water pressure sensor not con- nected or has short-circuited
F.74 Fault: Electrical problem in the water pressure sensor
F.75 Fault: Pressure sensor
F.76 The safety cut-out in the primary heat exchanger is defective
F.77 Fault: Condensate or smoke
F.78 Interruption to DHW outlet sensor at external controller
F.83 Fault: Dry fire
F.84 Fault: Flow/return temperature sensor
F.85 Fault: Temperature sensor
F.86 Fault: Underfloor heating contact
F.87 Fault: Electrodes
F.88 Fault: Gas valve
F.89 Fault: Pump
Connection No communication between the PCB and the user interface

 

Vaillant ecoTec exclusive Green iQ combi boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec exclusive Green iQ boiler installed:

Code Meaning
F.00 Interruption: Flow sensor
F.01 Interruption: Return sensor
F.02 Interruption: DHW outlet sensor
F.03 Interruption: Cylinder sensor
F.10 Short circuit: Flow sensor
F.11 Short circuit: Return sensor
F.12 Short circuit: DHW outlet sensor
F.13 Short circuit: Cylinder sensor
F.20 Safety switch-off: Temperature limiter
F.22 Safety switch-off: Low water pressure
F.23 Safety switch-off: Temp.spread too large
F.24 Safety switch-off: Temp. incr. too fast
F.25 Safety switch-off: Flue temp. too high
F.26 Fault: Fuel valve not working
F.27 Safety switch-off: Flame simulation
F.28 Start-up failure: Ignit. unsuccessful
F.29 Start-up failure: Ignit. unsuccessful
F.32 Fault: Fan
F.33 Pressure switch
F.35 Fault: Air/flue gas duct
F.42 Fault: Coding resistor
F.49 Fault: eBUS
F.55 Fault: CO sensor
F.56 Safety switch-off: CO limit exceeded
F.57 Fault: Measuring program
F.61 Fault: Fuel valve actuation
F.62 Fault: Fuel valve switch-off delay
F.63 Fault: EEPROM
F.64 Fault: Electronics/sensor
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.68 Fault: Flame signal unstable
F.70 Fault: Invalid Device Specific Number
F.71 Fault: Flow sensor
F.72 Fault: Flow/return sensor
F.73 Fault: Water press. sensor
F.74 Fault: Water press. sensor
F.75 Fault: Pump/ water shortage
F.77 Fault: Flue non-ret. valve/condens. pump
F.78 Interrupt.: DHW outlet sensor on ext. contr.
F.80 Fault: actoSTOR inlet sensor
F.81 Fault: cylinder charging pump
F.82 Fault: Ext. current anode
F.83 Fault: NTC temp. gradient
F.84 Fault: NTC temp. diff. implausible
F.85 Fault: NTCs fitted incorrectly
F.90 Fault: Communication
F.94 Fault: Vortex and differential pressure
LED actoSTOR module actoSTOR electronics status
Communication fault Communication fault

 

Vaillant ecoTec Plus Combination Store boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec Plus Combination Store boiler installed:

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 Product with integrated hot water generation: Short circuit warm start sensor/cylinder sensor Product with integrated hot water generation and 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
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 unsuccess- ful
F.29 Failure during operation: Re-ignition unsuc- cessful
F.32 Fan fault
F.42 Coding resistance fault (possible in combin- ation with F.70)
F.49 Fault: eBUS
F.52 Contact fault mass flow sensor/Venturi
F.53 Combustion regulation fault
F.54 Fault in the gas supply (in combination with F.28/F.29)
F.56 Combustion component fault
F.57 End comfort protection mode
F.61 Gas valve actuation fault
F.62 Gas valve switch-off delay
F.63 Fault: EEPROM
F.64 Fault: Electronics/NTC
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.68 Fault: Unstable flame signal
F.70 Invalid device specific number (DSN)
F.71 Flow NTC fault
F.72 Flow/return NTC fault
F.73 Water pressure sensor signal in the wrong range (too low)
F.74 Water pressure sensor signal outside cor- rect range (too high)
F.75 Fault: No pressure change detection when starting pump
F.77 Fault: Flue non-return flap/condensate pump
F.78 Interruption to DHW outlet sensor at the external controller
F.80 Interruption or short circuit of secondary heat exchanger inlet sensor; only in connection with F.91
F.81 actoSTOR charging pump defective; only in combination with F.91
F.83 Fault: Flow and/or return temperature sensor temperature change
F.84 Fault: Flow/return temperature sensor tem- perature difference implausible
F.85 Fault: Flow and return temperature sensors incorrectly installed
F.90 Communication with actoSTOR module interrupted
F.91 Sensor/actuator fault on actoSTOR module
F.92 Coding resistance fault
F.93 Poor combustion quality
LED actoSTOR module actoSTOR electronics status
Communication fault No communication with the PCB

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Vaillant boiler error codes

Vaillant system boiler error codes

 

Vaillant ecoFit Pure system boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoFit Pure System boiler installed:

Fault code Meaning
F.00 Fault: Flow temperature sensor
F.01 Fault: Return temperature sensor
F.10 Short circuit: Flow temperature sensor
F.11 Short circuit: Return temperature sensor
F.12 and F.91 Short circuit: Cylinder temperature sensor
F.13 Short circuit: Domestic hot water cylinder temperature sensor
F.20 Safety switch-off: Overheating temperat- ure reached
F.22 Safety switch-off: Low water pressure in the boiler
F.23 Safety switch-off: Temperature difference too great (NTC1/NTC2)
F.24 Safety switch-off: Temperature rise too fast
F.25 Safety switch-off: Flue gas temperature too high
F.27 Safety switch-off: Fault in flame detection
F.28 Fault: Ignition unsuccessful when starting up
F.29 Fault: Flame loss
F.32 Fan frost protection function active: Fan speed outside the tolerance values
F.49 eBUS fault: Voltage too low
F.61 Fault: Gas valve control system
F.62 Fault: Gas valve switch-off control
F.63 Fault: EEPROM
F.64 Fault: Electronics/sensor/analogue-to- digital converter
F.65 Fault: Electronics temperature too high
F.67 Value sent back by ASIC is incorrect (flame signal)
F.68 Fault: Unstable flame (analogue input)
F.70 Invalid product code (DSN)
F.71 Fault: Flow/return temperature sensor
F.72 Fault: Deviation in the water pressure sensor/return temperature sensor
F.73 Fault: Water pressure sensor not con- nected or has short-circuited
F.74 Fault: Electrical problem in the water pressure sensor
F.75 Fault: Pressure sensor
F.76 The safety cut-out in the primary heat exchanger is defective
F.77 Fault: Condensate or smoke
F.78 Interruption to DHW outlet sensor at external controller
F.83 Fault: Dry fire
F.84 Fault: Flow/return temperature sensor
F.85 Fault: Temperature sensor
F.86 Fault: Underfloor heating contact
F.87 Fault: Electrodes
F.88 Fault: Gas valve
F.89 Fault: Pump
Connection No communication between the PCB and the user interface

 

Vaillant ecoTec Plus system boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec Plus system boiler installed:

Message Possible cause
F.00 Interruption: Flow sensor Flow temperature sensor de- fective or not connected
F.01 Interruption: Return sensor Return temperature sensor de- fective or not connected
F.02 Interruption: DHW outlet sensor Cylinder temperature sensor for the shift-load cylinder defective or not connected
F.03 Interruption: Cylinder sensor Temperature sensor for the shift-load cylinder defective or not connected
F.10 Short circuit: Flow sensor Flow temperature sensor de- fective or has short-circuited
F.11 Short circuit: Return sensor Return temperature sensor de- fective or has short-circuited
F.12 Short circuit: DHW outlet sensor Cylinder temperature sensor defective or has short-circuited
F.13 Short circuit: Cylinder sensor Warm start sensor/cylinder tem- perature sensor defective or not connected
F.20 Safety switch-off: Tem- perature limiter Maximum temperature at the flow/return temperature sensor is too high when the safety cut- out function is operating using the NTC
F.22 Safety switch-off: Low water pressure No/insufficient water in the product or the water pressure is too low
F.23 Safety switch-off: Temp.spread too large Temperature spread too great. Water circulation too low
F.24 Safety switch-off: Temp. incr. too fast Temperature increase too fast
F.25 Safety switch-off: Flue temp. too high flue gas temperature too high
F.26 Fault: Fuel valve not working Gas valve assembly stepper motor defective or not connec- ted
F.27 Safety switch-off: Flame simulation Monitoring electrode reports an incorrect flame
F.28 Start-up failure: Ignit. unsuccessful Failure during start-up or igni- tion unsuccessful. Gas pressure monitor or thermal cut-out has been triggered.
F.29 Operating failure: Ignit. unsuccessful Gas supply interrupted intermit- tently. Re-ignition failed.
F.32 Fault: Fan Fan defective or not connected
F.42 Fault: Coding resistor Coding resistor or gas group resistor causes a short circuit
F.49 Fault: eBUS Undervoltage on the eBUS
F.52 Mass flow sensor not connected Mass flow sensor defective or not connected
F.53 Fault: Mass flow sensor Mass flow sensor defective
F.54 Fault: Boiler start No gas inlet pressure or insuffi- cient gas inlet pressure causes faults when the product is star- ted
F.55 Fault: CO sensor All-gas sensor defective or has short-circuited
F.56 Safety switch-off: CO limit exceeded Safety shutdown after the CO limit value is exceeded
F.57 Fault: Measuring pro- gram Regulation fault caused by cor- roded ignition electrode
F.61 Fault: Fuel valve actu- ation The gas valve assembly cannot be actuated
F.62 Fault: Fuel valve switch- off delay Delayed switch-off sequence for the gas valve after the flame is extinguished
F.63 Fault: EEPROM EEPROM faulty
F.64 Fault: Electronics/sensor Electronics, safety-relevant sensor or cable defective
F.65 Fault: Electronics temp. Electronics defective or too hot due to external influences
F.67 Fault: Electronics/flame Implausible flame signal
F.68 Fault: Flame signal un- stable Flame monitor reports an un- stable flame signal
F.70 Fault: Invalid Device Specific Number Incorrect/missing Device Specific Number or incorrect/missing coding resistor
F.71 Fault: Flow sensor Flow temperature sensor re- turns implausible values
F.72 Fault: Flow/return sensor Temperature difference between flow and return temperature sensor is too great
F.73 Fault: Water press. sensor (signal too weak) Water pressure sensor reports that the water pressure is too low
F.74 Fault: Water press. sensor (signal too strong) Water pressure too high
F.75 Fault: Pump/ water shortage Insufficient pressure jump de- tected when starting the pump
F.77 Fault: Flue non-ret. valve/condens. pump No flue non-return flap feed- back; condensate pump over- flow
F.78 Interrupt.: DHW outlet sensor on ext. contr. UK link box is connected without the domestic hot water temperature sensor being bridged
F.80 Fault: actoSTOR inlet sensor Inlet temperature sensor defect- ive or not connected
F.81 Fault: cylinder charging pump Cylinder is not fully charged after specified time
F.82 Fault: Ext. current anode External current anode defect- ive or not connected
F.83 Fault: NTC temp. gradi- ent Temperature difference between flow and return temperature sensor is too small
F.84 Fault: NTC temp. diff. implausible Temperature difference is im- plausible
F.85 Fault: NTCs fitted incor- rectly Flow/return temperat- ure sensors returning incorrect/implausible values
F.90 Fault: Communication Communication with actoSTOR interrupted
F.91 Fault: actoSTOR sensor Sensor on the actoSTOR is defective
F.92 Fault: Incorrect gas type The coding resistor on the PCB does not match the gas group that is entered
F.93 Fault: Check gas route Combustion quality outside the permitted range
F.94 Fault: Vortex and differen- tial pressure Sensors return implausible val- ues.
LED actoSTOR Modul actoSTOR communication status actoSTOR communication status: Not connected, Con- nection error, Connection active
Communication fault Communication fault between the display and the PCB in the electronics box

 

Vaillant ecoTec exclusive Green iQ system boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec exclusive Green iQ system boiler installed:

Code Meaning
F.00 Interruption: Flow sensor
F.01 Interruption: Return sensor
F.02 Interruption: DHW outlet sensor
F.03 Interruption: Cylinder sensor
F.10 Short circuit: Flow sensor
F.11 Short circuit: Return sensor
F.12 Short circuit: DHW outlet sensor
F.13 Short circuit: Cylinder sensor
F.20 Safety switch-off: Temperature limiter
F.22 Safety switch-off: Low water pressure
F.23 Safety switch-off: Temp.spread too large
F.24 Safety switch-off: Temp. incr. too fast
F.25 Safety switch-off: Flue temp. too high
F.26 Fault: Fuel valve not working
F.27 Safety switch-off: Flame simulation
F.28 Start-up failure: Ignit. unsuccessful
F.29 Start-up failure: Ignit. unsuccessful
F.32 Fault: Fan
F.33 Pressure switch
F.35 Fault: Air/flue gas duct
F.42 Fault: Coding resistor
F.49 Fault: eBUS
F.55 Fault: CO sensor
F.56 Safety switch-off: CO limit exceeded
F.57 Fault: Measuring program
F.61 Fault: Fuel valve actuation
F.62 Fault: Fuel valve switch-off delay
F.63 Fault: EEPROM
F.64 Fault: Electronics/sensor
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.68 Fault: Flame signal unstable
F.70 Fault: Invalid Device Specific Number
F.71 Fault: Flow sensor
F.72 Fault: Flow/return sensor
F.73 Fault: Water press. sensor
F.74 Fault: Water press. sensor
F.75 Fault: Pump/ water shortage
F.77 Fault: Flue non-ret. valve/condens. pump
F.78 Interrupt.: DHW outlet sensor on ext. contr.
F.80 Fault: actoSTOR inlet sensor
F.81 Fault: cylinder charging pump
F.82 Fault: Ext. current anode
F.83 Fault: NTC temp. gradient
F.84 Fault: NTC temp. diff. implausible
F.85 Fault: NTCs fitted incorrectly
F.90 Fault: Communication
F.94 Fault: Vortex and differential pressure
LED actoSTOR module actoSTOR electronics status
Communication fault Communication fault

 

Vaillant ecoTec Plus 48 and 64kW system boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec Plus 48kW or 64kW system boiler installed:

Message Possible cause
F.00 Flow temperature sensor interruption NTC plug loose/not plugged in
NTC sensor defective
Multiple plug loose/not plugged in
Interruption in the cable harness
F.01 Return temperature sensor interruption NTC plug loose/not plugged in
NTC sensor defective
Multiple plug loose/not plugged in
Interruption in the cable harness
F.03 Cylinder temperature sensor interruption NTC sensor defective
NTC plug loose/not plugged in
Connection to cylinder electron- ics defective
F.10 Flow temperature sensor short circuit NTC sensor defective
Short circuit in the cable har- ness
F.11 Return temperature sensor short circuit NTC sensor defective
Short circuit in the cable har- ness
F.13 Cylinder temperature sensor short circuit NTC sensor defective
Short circuit in the cable har- ness
F.20 Safety shutdown: Safety cut-out Flow NTC defective
Return NTC defective
Earth connection faulty
Stray spark via the ignition cable, ignition plug or ignition electrode
F.22 Safety shutdown: Water deficiency Insufficient/no water in the product.
Interruption in the cable harness
F.23 Safety shutdown: Temper- ature spread too great Pump blocked
Pump runs with insufficient out- put
Flow and return NTC connected the wrong way round
F.24 Safety shutdown: Temper- ature rise too fast Pump blocked
Pump runs with insufficient out- put
Non-return valve blocked
Non-return valve installed incor- rectly
System pressure too low
F.25 Safety shutdown: Flue gas temperature too high Flue gas safety cut-out plug is not plugged in or is loose
Interruption in the cable harness
F.27 Safety shutdown: Flame simulation Gas solenoid valve not leak- tight
Moisture on the PCB
Flame monitor defective
F.28 Ignition unsuccessful Gas stopcock closed
Gas valve assembly defective
The gas pressure monitor has been triggered
Gas flow pressure too low
The thermal isolator device has been triggered
Cable connections not plugged in/loose
Ignition system defective
PCB defective
Ionisation flow interrupted
Earthing defective
Air in the gas supply
Gas meter defective
Gas supply is interrupted
Flue gas circulation is incorrect
Ignition misfire
Diagnostics code D.085 incor- rectly set
Condensate siphon blocked
F.29 Ignition and check faults during operation – flame has gone out Gas valve assembly defective
Gas meter defective
The gas pressure monitor has been triggered
Air in the gas supply
Gas flow pressure too low
The thermal isolator device has been triggered
Cable connections not plugged in/loose
Ignition system defective
Ionisation flow interrupted
Earthing defective
PCB defective
F.32 Fan fault Plug on fan not plugged in or is loose
Multiple plug loose/not plugged in
Interruption in the cable harness
Fan blocked
Electronics defective
F.33 Air pressure switch fault Air/flue pipe blocked
Defective air pressure switch
Cable connections not plugged in/loose
Fan defective
F.33 Air pressure switch fault PCB defective
Excessive counter-pressure in the air/flue pipe
F.49 Fault: eBUS eBUS overload
Short circuit in the eBUS con- nection
Different polarities at the eBUS connection
F.61 Gas safety valve drive fault Short circuit in the cable har- ness
Gas valve assembly defective
PCB defective
F.62 Gas safety valve connec- tion fault PCB defective
The connection to the gas valve assembly has been interrup- ted/broken
F.63 Fault: EEPROM PCB defective
F.64 Fault: Electronics/NTC Flow NTC short circuit.
Return NTC short circuit
PCB defective
F.65 Electronics temperature fault Electronics overheated
PCB defective
F.67 Flame plausibility fault PCB defective
F.70 Invalid device specific number (DSN) Device Specific Number not set/is incorrect
Output range coding resistor missing or is incorrect
F.71 Flow temperature sensor fault The flow NTC reports a con- stant value
Incorrect position of the flow NTC
Flow NTC defective
F.72 Flow and/or return temper- ature sensor fault Flow NTC defective
Return NTC defective
F.73 Water pressure sensor signal in the wrong range (too low) Short circuit in the cable har- ness
Interruption in the cable harness
Water pressure sensor defect- ive
F.74 Water pressure sensor signal outside correct range (too high) Short circuit in the cable har- ness
Interruption in the cable harness
Water pressure sensor defect- ive
F.75 Pump fault/water defi- ciency Malfunction
D.149 = 1, pump blocked alarm
D.149 = 2, electrical pump fault alarm
D.149 = 3, pump dry running alarm
F.75 Pump fault/water defi- ciency D.149 = 5, no pressure peak detection
D.149 = 6, no feedback from the pump
D.149 = 7, incorrect pump de- tected
D.149 = 8, flow rate at the end of the purge programme is in- sufficient
F.77 Accessory fault (flue non- return flap, condensate pump, etc.) No feedback from the flue non- return flap or the feedback is incorrect
Flue non-return flap defective
No feedback from the condens- ate pump or the feedback is in- correct
F.83 Fault: Flow and/or return temperature sensor temperature change Water deficiency
Flow NTC: No contact
Return NTC: No contact
F.84 Fault: Temperature differ- ence at the flow and return tem- perature sensors Flow NTC installed incorrectly
Return NTC installed incorrectly
F.85 Flow and return temperat- ure sensors have been installed incorrectly (inverted) Flow/return NTC installed on the same/incorrect pipe

 

Vaillant ecoTec 46 and 65kW system boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec Plus 48kW or 64kW system boiler installed:

Code Meaning
F. 0 Flow temperature sensor interruption
F. 1 Return temperature sensor interruption
F.10 Flow NTC short circuit
F.11 Return NTC short circuit
F.13 Cylinder temperature sensor short circuit
F.20 Safety switch-off: Temperature limiter
F.22 Safety switch-off: Low water pressure
F.23 Safety switch-off: Temperature difference too great
F.24 Safety switch-off: Temperature rise too fast
F.27 Safety switch-off: Flame simulation
F.28 Failure during start-up: Ignition unsuccessful
F.29 Failure during operation: Re-ignition unsuccess- ful
F.32 Fan fault
F.49 Fault: eBUS
F.61 Gas valve actuation fault
F.62 Gas valve switch-off delay
F.63 Fault: EEPROM
F.64 Fault: Electronics/NTC
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.70 Invalid device specific number (DSN)
F.71 Flow NTC fault
F.72 Flow/return NTC fault
F.73 Water pressure sensor signal in the wrong range (too low)
F.74 Water pressure sensor signal outside correct range (too high)
F.75 Fault: No pressure change detection when start- ing pump
F.77 Fault: Flue non-return flap/condensate pump
con No communication with the PCB

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Vaillant boiler error codes

Vaillant regular boiler error codes

 

Vaillant ecoTec Plus regular boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoTec Plus regular boiler installed:

Fault code Meaning
F.00 Fault: Flow temperature sensor
F.01 Fault: Return temperature sensor
F.10 Short circuit: Flow temperature sensor
F.11 Short circuit: Return temperature sensor
F.12 and F.91 Short circuit: Cylinder temperature sensor
F.13 Short circuit: Domestic hot water cylinder temperature sensor
F.20 Safety switch-off: Overheating temperat- ure reached
F.23 Safety switch-off: Temperature difference too great (NTC1/NTC2)
F.24 Safety switch-off: Temperature rise too fast
F.25 Safety switch-off: Flue gas temperature too high
F.27 Safety switch-off: Fault in flame detection
F.28 Fault: Ignition unsuccessful when starting up
F.29 Fault: Flame loss
F.32 Fan frost protection function active: Fan speed outside the tolerance values
F.49 eBUS fault: Voltage too low
F.61 Fault: Gas valve control system
F.62 Fault: Gas valve switch-off control
F.63 Fault: EEPROM
F.64 Fault: Electronics/sensor/analogue-to- digital converter
F.65 Fault: Electronics temperature too high
F.67 Value sent back by ASIC is incorrect (flame signal)
F.68 Fault: Unstable flame (analogue input)
F.70 Invalid product code (DSN)
F.71 Fault: Flow/return temperature sensor
F.72 Fault: Deviation in the water pressure sensor/return temperature sensor
F.77 Fault: Condensate or smoke
F.78 Interruption to DHW outlet sensor at external controller
F.83 Fault: Dry fire
F.84 Fault: Flow/return temperature sensor
F.85 Fault: Temperature sensor
F.86 Fault: Underfloor heating contact
F.87 Fault: Electrodes
F.88 Fault: Gas valve
Connection No communication between the PCB and the user interface

 

Vaillant ecoFit Pure regular boiler error codes

Listed below are the most common fault codes that you might see if you have a Vaillant ecoFit Pure regular boiler installed:

Code Meaning
F.00 Flow temperature sensor interruption
F.01 Return temperature sensor interruption
F.10 Flow NTC short circuit
F.11 Return NTC short circuit
F.13 Warm start sensor/cylinder sensor short circuit
F.22 Safety switch-off: Low water pressure
F.23 Safety switch-off: Temperature difference too great
F.24 Safety switch-off: Temperature rise too fast
F.25 Safety switch-off: Flue gas temperature too high
F.27 Safety switch-off: Flame simulation
F.28 Failure during start-up: Ignition unsuccessful
F.29 Failure during operation: Re-ignition unsuccess- ful
F.32 Fan fault
F.49 Fault: eBUS
F.61 Fault: Gas valve regulation
F.62 Fault: Gas valve switch-off delay
F.63 Fault: EEPROM
F.64 Fault: Electronics/NTC
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.68 Fault: Unstable flame signal
F.70 Invalid device specific number (DSN)
F.71 Flow NTC fault
F.72 Flow/return NTC fault
F.73 Water pressure sensor signal in the wrong range (too low)
F.74 Water pressure sensor signal outside correct range (too high)
F.75 Fault: No pressure change detection when start- ing pump
F.76 Overheating protection on primary heat ex- changer has responded
F.77 Fault: Flue non-return flap/condensate pump
F.83 Fault: Flow and/or return temperature sensor temperature change
F.85 Fault: Flow and return temperature sensors incorrectly installed
F.87 Ignition transformer not connected
F.88 Gas valve not connected
F.89 Incorrect pump detected
con No communication with the PCB

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