Vaillant Repair Specialist

Repair Network has experienced gas-safe registered engineers for repairs and service of your Vaillant boiler.
Nationwide coverage, same or next day service, fixed cost repairs, one year guarantee.

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Vaillant Boilers

Vaillant boilers are available as combi, system and regular (open vent) models.
Vaillant began in 1874 in Germany, patenting its first gas bath boiler ‘closed system’ in 1894 and the world’s first “wall-hung” heater in 1904. For the next 100+ years Vaillant continued its tradition of innovation, introducing numerous “first of its kind” heating products. Recent focus is in technologies based on renewable energies.
Vaillant is one of Europe’s most popular boiler brands, has the “Superbrand” accolade in the UK and has earned the prestigious Quiet Mark award.
In the UK, Vaillant products are sold under the Glow-worm brand name and are manufactured in Belper, Derbyshire.
Vaillant boilers have a guarantee of up to 10 years (depending on the model and installation conditions) under which you agree to an annual service.

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Require some form of repairs!

Book a certified technician with the tools and experience to repair all your Ideal Vaillant!

03333449104

Available 9 AM to 7 PM

Same day or next day repair

Why Repair Network Nationwide?

When your boiler breaks down you want a repair service that is quick, reliable and affordable.
Repair Network is committed to providing a prompt service by a qualified, local technician.
Appointment times  are set to suit you to limit the frustration of running a household without a boiler and to avoid you having to take too much time out to wait for a service call. We aim for same or next day service.
Our boiler repair service has nationwide coverage with all technicians being gas registered to ensure they are not only qualified to work on your boiler but that the repair will be carried out safely. We also guarantee that the engineer arriving at your home has experience working on your brand of boiler.
Our aim is always to fix your boiler to prevent you having to undergo the expense of a boiler replacement. Our repair, not replace policy is underlined by a one-year guarantee.
Check out our enquiry form and see just why we’re rated by our customers as very good on Trustpilot.

What we cover and what we don’t

Customer satisfaction is paramount to us so we are transparent with our pricing.
All our repairs are at a fixed price and there are no surprises with hidden fees. The fixed price includes labour and the cost of genuine brand-approved parts.
All our boiler repair work is covered by a one-year guarantee so you have peace of mind should anything go wrong.
If the engineer is unable to repair your Vaillant boiler, they will provide a free, no-obligation quote for a new boiler and installation.

What are the error codes Vaillant boiler and what do the mean?

Determine the model of your Vaillant boilers and look to the ahead for the various error codes and what they mean.

Find your Error Code

Vaillant ecoTec Pro combi boiler error codes:

CodeError Message
F.00 Interruption: Flow sensor
F.01 Interruption: Return sensor
F.10 Short circuit: Flow sensor
F.11 Short circuit: Return 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 Operating failure: Ignit. unsuccessful
F.32 Fault: Fan
F.49 Fault: eBUS
F.61 Fault: Fuel valve actuation
F.92 Fault: Fuel valve switch off delay
F.63 Fault: EPROM
F.64 Fault: Electronics/sensor
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.68 Fault: Flame signal un stable
F.70 Fault: Invalid Device Specific Number
F.71 Fault: Flow sensor
F.72 Fault: Flow/return sensor
F.73 Fault: Water press. sensor (signal too weak)
F.74 Fault: Water press. sensor (signal too strong)
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.83 Fault: NTC temp. gradient
F.84 Fault: NTC temp. diff. implausible
F.85 Fault: NTCs fitted incorrectly
Communication fault

Vaillant ecoTec Plus combi boiler error codes:

CodeMessage
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: Tem- perature 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 Operating failure: Ignit. unsuccessful
F.32 Fault: Fan
F.42 Fault: Coding resistor
F.49 Fault: eBUS
F.52 Mass flow sensor not connected
F53 Fault: Mass flow sensor
F.54 Fault: Boiler start
F.55 Fault: CO sensor
F.56 Safety switch-off: CO limit exceeded
F.57 Fault: Measuring pro- gram
F.61 Fault: Fuel valve actu- ation
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 un- stable
F.70 Fault: Invalid Device Specific Number
F.71 Fault: Flow sensor
F.72 Fault: Flow/return sensor
F.73 Fault: Water press. sensor (signal too weak)
F.74 Fault: Water press. sensor (signal too strong)
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. gradi- ent
F.84 Fault: NTC temp. diff. implausible
F.85 Fault: NTCs fitted incor- rectly
F.90 Fault: Communication
F.91 Fault: actoSTOR sensor
F.92 Fault: Incorrect gas type
F.93 Fault: Check gas route
F.94 Fault: Vortex and differential pressure
LED actoSTOR Modul actoSTOR communication status
Communication fault

Vaillant ecoFit Pure combi boiler error codes:

CodeError Message
F.00 Interruption: Flow sensor
F.01 Interruption: Return sensor
F.10 Short circuit: Flow sensor
F.11 Short circuit: Return 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 Operating failure: Ignit. unsuccessful
F.32 Fault: Fan
F.49 Fault: eBUS
F.61 Fault: Fuel valve actuation
F.92 Fault: Fuel valve switch off delay
F.63 Fault: EPROM
F.64 Fault: Electronics/sensor
F.65 Fault: Electronics temp.
F.67 Fault: Electronics/flame
F.68 Fault: Flame signal un stable
F.70 Fault: Invalid Device Specific Number
F.71 Fault: Flow sensor
F.72 Fault: Flow/return sensor
F.73 Fault: Water press. sensor (signal too weak)
F.74 Fault: Water press. sensor (signal too strong)
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.83 Fault: NTC temp. gradient
F.84 Fault: NTC temp. diff. implausible
F.85 Fault: NTCs fitted incorrectly
Communication fault

Vaillant ecoTec exclusive Green iQ combi boiler error codes:

CodeMeaning
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
actoSTOR electronics status
Communication fault

Vaillant ecoTec Plus Combination Store boiler error codes:

CodeMeaning
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 unsuccessful
F.29 Failure during operation: Re-ignition unsuccessful
F.32 Fan fault
F.42 Coding resistance fault (possible in combination 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 correct 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 temperature 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
actoSTOR electronics status
No communication with the PCB

Vaillant ecoFit Pure system boiler error codes:

Fault codeMeaning
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 temperature 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 connected 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
Con No communication between the PCB and the user interface

Vaillant ecoTec Plus system boiler error codes:

CodeMessage
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 Operating failure: Ignit. unsuccessful
F.32 Fault: Fan
F.42 Fault: Coding resistor
F.49 Fault: eBUS
F.52 Mass flow sensor not connected
F.53 Fault: Mass flow sensor
F.54 Fault: Boiler start
F.55 Fault: CO sensor
F.56 Safety switch-off: CO limit exceeded
F.57 Fault: Measuring pro- gram
F.61 Fault: Fuel valve actu- ation
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 un- stable
F.70 Fault: Invalid Device Specific Number
F.71 Fault: Flow sensor
F.72 Fault: Flow/return sensor
F.73 Fault: Water press. sensor (signal too weak)
F.74 Fault: Water press. sensor (signal too strong)
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. gradi- ent
F.84 F.84 Fault: NTC temp. diff. implausible
F.85 F.85 Fault: NTCs fitted incorrectly
F.90 F.90 Fault: Communication
F.91 Fault: actoSTOR sensor
F.92 Fault: Incorrect gas type
F.93 Fault: Check gas route
F.94 Fault: Vortex and differential pressure
LED LED actoSTOR Modul actoSTOR communication status

Vaillant ecoTec exclusive Green iQ system boiler error codes:

CodeMeaning
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 electronics status
Con Communication fault

Vaillant ecoTec Plus 48 and 64kW system boiler error codes:

CodeMessage
F.00 Flow temperature sensor interruption
F.01 Return temperature sensor interruption
F.03 Cylinder temperature sensor interruption
F.10 Flow temperature sensor short circuit
F.11 Return temperature sensor short circuit
F.13 Cylinder temperature sensor short circuit
F.20 Safety shutdown: Safety cut-out
F.22 Safety shutdown: Water deficiency
F.23 Safety shutdown: Temperature spread too great
F.24 Safety shutdown: Temperature rise too fast
F.25 Safety shutdown: Flue gas temperature too high
F.27 Safety shutdown: Flame simulation
F.28 Ignition unsuccessful
F.29 Ignition and check faults during operation – flame has gone out
F.32 Fan fault
F.33 Air pressure switch fault
F.49 Fault: eBUS
F.61 Gas safety valve drive fault
F.62 Gas safety valve connection fault
F.63 Fault: EEPROM
F.64 Fault: Electronics/NTC
F.65 Electronics temperature fault
F.67 Flame plausibility fault
F.70 Invalid device specific number (DSN)
F.71 Flow temperature sensor fault
F.72 Flow and/or return temperature sensor 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 Pump fault/water deficiency
F.77 Accessory fault (flue non- return flap, condensate pump, etc.)
F.83 Fault: Flow and/or return temperature sensor temperature change
F.84 Fault: Temperature difference at the flow and return temperature sensors
F.85 Flow and return temperature sensors have been installed incorrectly (inverted)

Vaillant ecoTec 46 and 65kW system boiler error codes:

CodeMessage
F.00 Flow temperature sensor interruption
F.01 Return temperature sensor interruption
F.03 Cylinder temperature sensor interruption
F.10 Flow temperature sensor short circuit
F.11 Return temperature sensor short circuit
F.13 Cylinder temperature sensor short circuit
F.20 Safety shutdown: Safety cut-out
F.22 Safety shutdown: Water deficiency
F.23 Safety shutdown: Temperature spread too great
F.24 Safety shutdown: Temperature rise too fast
F.25 Safety shutdown: Flue gas temperature too high
F.27 Safety shutdown: Flame simulation
F.28 Ignition unsuccessful
F.29 Ignition and check faults during operation – flame has gone out
F.32 Fan fault
F.33 Air pressure switch fault
F.49 Fault: eBUS
F.61 Gas safety valve drive fault
F.62 Gas safety valve connection fault
F.63 Fault: EEPROM
F.64 Fault: Electronics/NTC
F.65 Electronics temperature fault
F.67 Flame plausibility fault
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 starting pump
F.77 Fault: Flue non-return flap/condensate pump
con No communication with the PCB

Vaillant ecoTec Plus regular boiler error codes:

Fault codeMeaning
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 temperature 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: 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
Con No communication between the PCB and the user interface

Vaillant ecoFit Pure regular boiler error codes:

CodeMeaning
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 unsuccessful
F.32 Fan fault
F.49 Fault: eBUS
F.61 Fault: Gas valve regulation
F.62 Fault: Gas valve switch-off delay
F.63 ault: 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 starting 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