Central Heating Engineers London

Central Heating Engineers London

Central Heating Engineers London

In our modern-day homes, central city-systems seem to always have to stay. This functional and effective heating system is one of the best every homeowner will wish to have in their home to take them through the cold winter months in the city of London. Are you planning to install one of this in your home? Then you will be needing the services of a central heating engineers London.

When it comes to installing, repairing and maintaining central heating systems, we are a force to be reckoned with. Over services cut across just providing a reliable system for your home, we are here to provide an environmentally friendly heating system that will give you the best.

We understand your needs as an individual. And as such, our services as standard central heating engineers London covers good customer services, topnotch repairs, and servicing, effective and swift installation.

London Central Heating Engineers

Unlike others, we don’t just fix your heating problems never to take time out to check how your heating system is coming up. It’s our habit to always check back and see if you are having any form of difficulties and get it fixed. With this, you should be assured that the guarantee we have in place for you aren’t just mere promises but tasks that we consider as part of our services.

Besides, our team comprises of not just engineers but also technicians and electricians with their respective specialties. This automatically means none of our personnel is a “Jack of all trades, master of none”. We work collectively as a team with the primary objective of giving you the best of home heating.

Finally

Do you wish to replace your old central heating systems with new ones? We take care of that as well. Being competent Central Heating Engineers London, we will help you to make the right decision as to which central heating system will be best for your home. And at the same time help you with the proper recycling of your old central heating.

Our goal is to give you the best and we aren’t going to compromise on that for any reason whatsoever.

Get In Touch

You can contact Master Gas 24 hours a day and a member of our team will only be pleased to receive your call request.
By using Master Gas you can rest assured that your job will be completed by experts and to your satisfaction, not forgetting, of course, our workmanship guarantee. Call today
07948 009 319

 

Boiler Replacement London

Baxi Boiler Error Codes

Fault CodePossible Cause
E20Central heating NTC error
E28Error with the NTC (Negative Temperature Coefficient) flue, air pressure switch or blocked flue or condensate
E50Hot water NTC (Negative Temperature Coefficient) error
E110Thermostat operated safety
E119Water pressure switch error – not operated.
E125Primary circuit error circulation fault
E130Flue NTC (Negative Temperature Coefficient) operation error
E133Gas supply error or flame failure
E160Fan or fan wiring error
E193Pre-circulation error
Fault CodePossible Cause
110Overheated – try bleeding your radiators
117Water pressure too high
118Water pressure too low
125Water circulation fault
133Safety time to establish flame exceeded
E10Outdoor sensor error
E20Central heating thermistor sensor fault
E28Flue thermistor fault
E54Domestic hot water (DHW) flow sensor fault
E78Water pressure sensor fault
E100Internal clock time error on printed circuit board (PCB)
E109Poor circulation
110Overheat – try bleeding your radiators
111Maximum limit of flow temperature
117Water pressure too high
118Water pressure too low
119System pressure too low
125Water circulation fault
127Legionella (cause of Legionnaires’ disease) protection temperature not reached
128Loss of flame during operation
133Safety time to establish flame exceeded
153Forced reset unit unlocked
160Fan fault
162Air pressure switch error
164Pressure Sensor Error (UK) – Heating flow switch error (Ireland)
166Air pressure switch fault
270Dry fire
432Earth connector error
433Heat exchanger temperature exceeded (greater than 95 degrees)
Fault CodePossible Cause
1 green flashBoiler temperature reached. No action required.
3 green flashesTemporary flame loss. Boiler will self reset, if fault continues you will see 3 red flashes.
4 green flashesCommunication error between printed circuit board (PCB) and control. Temporary error, will self reset.
5 green flashesParameter error on printed circuit board (PCB). Temporary error, will self reset
6 green flashesMiscellaneous error. Temporary error, will self reset.
1 red flashSensor error, temperature fault or flow fault.
2 red flashesBoiler overheat tripped
3 red flashesIgnition fault. Boiler has attempted to light 5 times and failed.
4 red flashesFan fault
5 red flashesParameter storage unit (PSU) error.
6 red flashesMiscellaneous error.
Fault CodePossible Cause
E10Outdoor sensor fault
E20Central heating thermistor sensor error
E28Flue thermistor error
E110Boiler overheat error
E119Low water pressure error
E125Primary water circulation error
E131Flue overheat lockout error
E133Ignition error
E160 / E161Fan error
E164Pressure sensor fault
E167Printed circuit board (PCB) error
E168Printed circuit board (PCB) lockout error
E193Circulation error
Fault CodePossible Cause
H.01 – .00Loss of communication between gas valve and boiler board. Possible fault in air/gas unit or loose connection to gas valve.
H.01 – .05Difference between the flow and return temperature is too high, sensor error or insufficient circulation.
H.01 – .08Sensor fault, flow temperature increasing too fast in heating mode or insufficient circulation.
H.01 – .14Maximum flow temperature value exceeded or insufficient circulation – temporary fault.
H.01 – .18No water circulation, insufficient circulation or sensor error.
H.01 – .21Temporary error – flow temperature increasing too fast in domestic hot water (DHW) mode, insufficient circulation or sensor error.
H.02 – .02Temporary error – no input of parameters C1/C2. Printed circuit board (PCB) not configured.
H.02 – .03Temporary error- incorrect configuration settings C1/C2.
H.02 – .04Temporary error- parameter fault. Incorrect parameters.
H.02 – .06Temporary error caused by system water pressure, water leak on boiler, water leak on system.
H.03 -.00Temporary error with communication, negative temperature coefficient thermostat (NTC) or flue sensor. Sensor could also be unconnected or have a bad connection.
H.03 – .01Communication error with the printed circuit board (PCB)
H.03 – .02Flame error – no flame during operation.
E.00 – .04Return temperature sensor open-circuit. Sensor not or badly connected.
E.00 – .05Return temperature sensor short-circuit. Sensor not connected or badly connected.
E.01 – .02Temperature measured by return sensor greater than flow sensor.
E.01 – .04Loss of flame detected 5 times in 24 hours (with burner on).
E.01 – .11Incorrect fan speed – external draught over the boiler or defective gas/air unit.
E.01 – .12Requires reset – temperature measured by return sensor greater than flow temperature.
E.01 – .17Reset the boiler – no circulation, sensor fault either not connected or has a bad connection.
E.01 – .20Maximum flue gas temperature reached. No circulation or sensor fault.
E.02 – .00Reset button has been pressed.
E.02 – .07No or low system water pressure. system pressure less than 0.5bar
E.02 – .16Permanent fault caused by channel service unit (CSU) time-out or printed circuit board (PCB) damage.
E.02 – .17Loss of communication between gas valve and boiler printed circuit board (PCB) or fault in air/gas unit.
E.02 – .19Jumper 1 changed – check position of jumper 1.
E.02 – .20Jumper 2 changed – check position of jumper 2.
E.02 – .21Jumper 3 changed – check position of jumper 3.
E.02 – .47Wiring to external device error.
E.02 – .48Configuration to external device unsuccessful – check pairing to external device.
E.04 – .00Gas valve error – gas valve not detected.
E.04 – .01Flow temperature sensor short-circuited. Sensor not or badly connected, bad connection or sensor fault.
E.04 – .02Permanent fault. Flow temperature sensor open-circuited, sensor not or badly connected, bad connection or sensor fault.
E.04 – .03Permanent fault. Critical flow temperature reached, non-existent or insufficient circulation.
E.04 – .04Permanent fault. Flue temperature sensor short-circuited, sensor not or badly connected, bad connection or sensor fault.
E.04 – .05Permanent fault. Flue temperature sensor short-circuited, sensor not or badly connected, bad connection or sensor fault.
E.04 – .06Permanent fault. Critical flue gas temperature value reached, no circulation or sensor fault.
E.04 – .08Permanent fault. Maximum safe temperature value reached, safety thermostat open-circuited, no circulation, sensor not or badly connected, bad connection or sensor fault.
E.04 – .10Failure to light (could be gas supply issue).
E.04 – .12Permanent fault. False flame signal, short-term fluctuation of the mains, ionization current present even though there is no flame, the burner remains very hot (CO2 too high) or defective gas/air unit.
E.04 – .13Permanent fault. Fan rotor blocked, fan seized or wiring to fan damaged.
E.04 – .17Permanent fault. Problem with gas valve or defective gas/air unit.
Fault CodePossible Cause
E09Gas valve connection cable.
E10External probe fault.
E12Differential water flow switch fault (still open).
E13Differential water flow switch fault (still closed).
E15Gas valve command fault.
E20Central heating negative temperature coefficient (NTC) thermostat fault.
E28Flue negative temperature coefficient (NTC) thermostat fault.
E40Central heating return negative temperature coefficient (NTC) thermostat fault.
E50Domestic hot water (DHW) negative temperature coefficient (NTC) thermostat sensor fault (tank boiler) (s.c.) or DHW NTC sensor fault (tank boiler) (o.c.).
E83/E84/E85/E86/E87No communication.
E109Pre-circulation fault.
E110
  • Boiler max temperature exceeded for gradient (probable pump jammed or air in the circuit
  • Boiler max temperature exceeded for overtemperature (probable pump jammed or air in the circuit
  • Safety thermostat sensor tripped.
E118Primary system water pressure too low (< 0.5 bar).
E125Circulation fault (primary).
E128Frequent flame failure (12 times).
E129Safety error for frequently loss of flame with max correction during the ignition during Calibration Function.
E130Flue thermostat sensor tripped (lockout).
E133Failure to light (could be a gas supply issue).
E134Elapsed time gas valve open without gas
(short request in a short period)
E135Interruption of gas supply (internal error).
E154Flow/return sensor temperature test.
E160Fan or fan wiring fault.
E163Domestic hot water (DHW) negative temperature coefficient (NTC) thermostat sensor fault (s.c.) or DHW NTC sensor fault (o.c.).
E270Circulation fault (dry fire).
E317Wrong power supply electrical frequency (Hz).
E321Hot water negative temperature coefficient (NTC) fault.
E384False flame.
E385Under voltage.
E430Water pressure temporary test.
E430 + Flame ‘crossed’Water pressure test failed.
Fault CodePossible Cause
1 Green FlashBoiler temperature reached – no action required
3 Green FlashesTemporary flame loss – this is a temporary error, the system should reset on its own
4 Green FlashesCommunication error between printed circuit board (PCB) and Control – this is a temporary error, the system should reset on its own
5 Green FlashesParameter error on parameter storage unit (PSU) or printed circuit board (PCB) – this is a temporary error, the system should reset on its own.
6 Green FlashesMiscellaneous error
1 Red FlashSensor error, sensor fault, temperature fault or flow fault – this is a temporary error, the system should reset on it’s own.
2 Red FlashesBoiler overheat tripped
3 Red FlashesIgnition fault. Boiler has attempted to light 5 times and failed
4 Red FlashesFan Fault
5 Red FlashesParameter storage unit (PSU) error
6 Red FlashesMiscellaneous
Fault CodePossible Cause
E0Temperature sensor fault
E1Overheated – try bleeding your radiators
E2Poor circulation – try bleeding your radiators
E3Printed circuit board (PCB) fault
E4Ignition failure – try bleeding your radiators
E10Poor/No circulation
E12Printed circuit board (PCB) Fault
E13Heat exchanger thermal fuse tripped
E83 / 84 / 85 / 86 / 87Fan fault normally E8
Fault CodePossible Cause
E53Poor combustion – flue terminal may be blocked
E110Overheated – try bleeding your radiators
E117System water pressure high – try bleeding water from your radiators
E118System water pressure low
E125Overheat – try bleeding your radiators
E133Gas supply fault
E4Ignition failure
E09Gas valve wiring fault
E10Outdoor sensor error
E15Gas valve connection fault
E20Central heating thermistor sensor fault
E28Flue thermistor fault
E40Central heating return thermistor fault
E53Flue obstruction
E55Calibration required
E78Water pressure sensor fault
E92Combustion test alarm during auto-setting
E109Poor circulation
E110Boiler overheat tripped
E117System pressure high (>2.9 Bar)
E118System pressure low(< 0.5bar)
E125Primary water circulation fault
E128Loss of flame during operation
E129Loss of flame during calibration
E133Ignition fault
E135Internal error
E154Primary flow fault
E160Fan fault
E270Dry fire
E317Wrong power supply (Hz)
E321Not water thermistor fault
E384Flame detected when gas valve off
E385Low voltage (less than 195v)
Fault CodePossible Cause
FLASH FLASH ONFan error
FLASH OFF FLASHVoltage less than 180V
FLASH OFF ONOverheat lockout
FLASH ON FLASHPrinted circuit board (PCB) error
FLASH ON ONPrinted circuit board (PCB) fault
OFF OFF OFFNo power
ON FLASH FLASHCirculation error or dry fire
ON FLASH ONThermistor error
ON OFF FLASHLive and neutral reversed error
ON OFF ONIgnition lockout error
ON ON FLASHPrinted circuit board (PCB) error
ON ON ONLow voltage wiring harness error

Glow Error Codes

Boiler ModelFault CodeCause of Problem
BetacomRed LED onLockout – low water pressure (increase pressure to 1.5bar) and reset boiler
BetacomRed LED flashingOverheat – check both overheat stats
BetacomYellow LED flashingTurn domestic hot water (DHW) control knob into temperature range and turn central heating (CH) temperature control knob into power (reset position) and wait for minimum of 30 seconds before turning into either summer or temperature position
BetacomYellow LED onFlame present on the burner
BetacomGreen LED onBoiler ready for operation
BetacomGreen LED offNo power to boiler – Check for 230volts into the appliance, check fuse on printed circuit board (PCB)
Betacom / Ultracom₂ cxi / sxi / 35F00 / F10 / F71Flow heating temperature sensor fault
Betacom / Ultracom₂ cxi / sxi / 35F01 / F11Return heating temperature sensor fault
Betacom / Ultracom₂ cxi / sxi / 35F20Overheating fault
Betacom / Ultracom₂ cxi / sxi / hxi / 35 / Flexicom cx / hx / sxF9 / F22Low water pressure (or ignition temperature rise too slow)
Betacom / Ultracom₂ cxi / sxi / 35F26 / F77Fault in gas valve
Betacom / Ultracom₂ cxi / sxi / 35 / CI / hxi / Xtramax HEF27 / F16Flame detection fault
All BoilersF28 / F1 / F4Ignition fault (flame detection)
Betacom / Ultracom₂ cxi / sxi / 35F29Loss of flame during operation
Betacom / Ultracom₂ cxi / sxi / 35F32Incorrect air pressure
Betacom / Ultracom₂ cxi / sxi / 35F49EBUS voltage fault
Betacom / Ultracom₂ cxi / sxi / 35F61 / F62 / F63 / F64 / F65 / F67Fault in the main board
Betacom / Ultracom₂ cxi / sxi / 35F68Fluctuation of flame signal
Betacom / Ultracom₂ cxi / sxi / 35F70User interface incompatible with the main board
Betacom / Ultracom₂ cxi / sxi / 35F72 / F84Permanent temperature difference between flow and return heating sensors
Betacom / Ultracom₂ cxi / sxi / 35F73 / F74Heating circuit pressure sensor fault
Betacom / Ultracom₂ cxi / sxi / 35F76Thermal fuse fault
Betacom / Ultracom₂ cxi / sxi / 35F83Thermal fuse fault
Betacom / Ultracom₂ cxi / sxi / 35F85Flow and Return heating sensor fault
Betacom / Ultracom₂ cxi / sxi / 35F86Underfloor heating contact fault
All BoilersERR / F12 / F18User interface fault
Betacom cTemperature 30 flashingFault on central heating (CH) thermistor
Betacom cTemperature 40 flashingFault on DHW thermistor
Betacom cTemperature 50 flashingFault on outside sensor
Betacom cTemperature 60 flashingLow system pressure
Betacom cTemperature 70 flashingFault on APS
Betacom cTemperature 80 flashingOverheat open circuit
Betacom cTemperature 90 flashingFlame or gas failure
Compact e / sNo DHWCheck dhw microswitch / Check external controls, Please test for 230V on switch live contact
Compact e / sNo C/HCheck dhw microswitch if dhw demand led is lit / Check external controls, Please test for 230V on switch live contact
Compact e / sNo C/H but boiler is firingCheck divertor motor and cartridge / Check external controls, Please test for 230V on switch live contact
Compact e / sBoiler locks out within 10 secondsCheck pump proving switch, air pressure switch and overheat state / Check pump proving switch, air pressure switch and overheat stat
Compact e / sPoor burner pressureCheck burner pressure/ignition adjustment pots on PCB
Ci Range (plus) / Si rangeF2Fan/APS
All BoilersF5Overheat Fault
All BoilersF6Central heating flow thermistor
All BoilersF7Domestic hot water thermistor
All BoilersF8Tank thermistor fault
sxi / si / ci (plus) range / Xtramax HEF9Water pressure sensor fault (please contact GW technical department for further information)
All boilersF10Central return flow thermistor
All boilersF11Main board connection fault
Ci (plus) / cxi / hxi / si / sxi rangeF12Connection fault between main printed circtuit board (PCB) and display PCB
Ci (plus) / cxi / hxi / si / sxi rangeF13Main pcb connection fault
Ci (plus) / cxi / hxi / si / sxi rangeF14Central heating flow temperature > 95 degrees
Ci (plus) / cxi / si / sxi rangeF15Gas valve stepper motor fault
Ci (plus) / cxi / hxi / si / sxi range / Xtramax HEF17Power supply is less than 170v
Ci (plus) / cxi / hxi / si / sxi range / Xtramax HEF19Central heating thermistor unplugged
Ci (plus) / cxi / hxi / si / sxi range / Xtramax HEF20Software incompatibility
cxi / hxi / sxi range / Flexicom cxF24Central heating return temperature > 90 degrees
cxi / hxi / sxi / Xtrafast 96/120 / Xtrafast 96/120E1F25 / F26 / F11Poor circulation
ci rangeF3Air fault
ci rangeF3Air fault
cxi / sxi / hxi range/ Xtramax HEF2 / F3Fan
cxi / sxi range / Flexicom cx / hx / sx / hxi / Ultracom cxi / cx / hxi / sxi / Ultrapower sxiF3Fan unable to reach ignition speed
Flexicom cx / hx / sx / hxi / Ultracom cxi / cx / hxi / sxiF9Water pressure sensor fault, blocked flow filter or pump fault
Flexicom cx / hx / sxF11Flow and or return thermistor fault
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HEF13PCB memory or sensing fault
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HEF14Gas valve control defective
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HEF15E-bus voltage failure
All boilersF25 / F23Circulation fault
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxiF43Generic error
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxiF70Software incompatible
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxiF73Unable to see pump activate
Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxiF77Condensate pump error (optional)
hxi rangeF9Earlier models only (please contact GW technical department for further information)
hxi rangeF9Earlier models only (please contact GW technical department for further information)
Ultracom₂ 35 StoreF02 / F12Hot water temperature sensor fault
Ultracom₂ 35 StoreF03 / F13 / F79Storage tank temperature sensor fault
Ultracom₂ 35 StoreF81Overheating of hot water circuit
All UltracomNo display or Erloose connection X51
Xtramax HE RangeF24Cental heating return temperature > 90 degrees
Xtramax HE RangeF25Maximum temperature rise slope
Xtramax HE RangeF26Maximum delta temperature
Xtrafast 96/120 RangeF00No fault/td>
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF00No fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF02Air flow fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF05Overheating
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF06Central heating thermistor/wiring fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF08Storage vessel thermistor/wiring fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF09System pressure sensor fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF10Fan fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF13Main printed circuit board (PCB) fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF14Central heating flow temperature > 97 degrees
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF15Gas mechanism fault
Xtrafast 96/120 Range / Xtrafast 96/120E1 RangeF20Communication fault
Fault CodeCause of Problem
F.00Flow temperature sensor
F.00Flow temperature sensor
F.10Flow temperature sensor short circuit
F.11Flow temperature sensor short circuit
F.12 and F.91Cylinder temperature sensor short circuit
F.13Domestic hot water cylinder temperature sensor short circuit
F.20Safety switch-off – overheating temperature reached
F.22Safety switch-off – low water pressure in the boiler
F.23Safety switch-off – temperature difference too great (NTC1/NTC2)
F.24Safety switch-off – temperature rise too fast
F.25Safety switch-off – flue gas temperature too high
F.27Safety switch-off – fault in flame detection
F.28Ignition unsuccessful when starting up
F.29Flame loss
F.32Fan frost protection function active – fan speed outside the tolerance values
F.33Fan frost protection function active – air pressure switch fault
FA9eBUS fault – voltage too low
F.61Gas valve control system fault
F.82Gas valve switch-off control fault
F.83EEPROM fault – electronics defective
F.64Electronics/sensor/analogue-to-digital converter fault
F.85Electronics temperature too high
F.67Value sent back by ASIC is incorrect (flame slgnal)
F.88Unstable flame (analogue input), underfloor heating contact or gas valve fault
F.70Invalid product code (DSN)
F.71Flow/return temperature sensor
F.72Deviation in the water pressure sensor/return temperature sensor
F.73Water pressure sensor not connected or has short-circuited
F.74Electrical problem in the water pressure sensor
F.75Pressure sensor fault
F.78The safety cut-out in the primary heat exchanger is defective
F.77Fault: Condensate or smoke
F.78Interruption to domestic hot water (DHW) outlet sensor at external controller
F.83Burner temperature sensor fault
F.84Flow/return temperature sensor fault
F.85Temperature sensor fault
F.87Electrodes fault
F.89Pump fault
ConnectionNo communication between the printed circuit board (PCB) and the user interface

Ideal Error Codes

Fault DescriptionSystem Behaviour
L1Flow temperature overheat lockout or no water flow lockout
L2Ignition lockout
LC5 restarts within 15 minutes
L6False flame lockout
FAFlow return reversed
FDNo water flow
F2 or FN or LNFlame loss
F3Fan fault
L4 or F4Control / no flow thermistor fault
L5 or F5Return thermistor fault
F6Outside sensor fault
F7Low mains voltage Contact electricity provider
F9, L9, F8 or L8Printed circuit board (PCB) unconfigured or fault
FUDiff greater than 50c check isolation valves are open
Fault CodeSystem Behaviour
C0Boiler chip card (BCC) activation fault
C2Boiler chip card (BCC) fault
F1Low water pressure
F2Flame loss
F3Fan fault
F4Flow thermistor fault
F5Return thermistor fault
F6Outside sensor failure
F7Low mains voltage
F9Unconfigured printed circuit board (PCB)
L1Flow temperature overheat or no water flow
L2Flame loss
L55 boiler resets in 15 minutes
L6False flame lockout

 

Fault CodeSystem Behaviour
0The boiler is in standby mode awaiting either a central heating call or hot water demand
CThe boiler has a call for central heating but the appliance has reached the desired temperature set on the boiler
DThe boiler has a call for hot water but the appliance has reached the desired temperature set on the boiler
CThe boiler is operating in central heating mode
dThe boiler is operating in hot water mode
FThe boiler is operating in frost mode
Fault DescriptionSystem Behaviour
L1Flow temperature overheat lockout or no water flow lockout
L2Ignition lockout
LC5 restarts within 15 minutes
L6False flame lockout
FAFlow return reversed
FDNo water flow
F2 or FN or LNFlame loss
F3Fan fault
L4 or F4Control / no flow thermistor fault
L5 or F5Return thermistor fault
F6Outside sensor fault
F7Low mains voltage Contact electricity provider
F9, L9, F8 or L8Printed circuit board (PCB) unconfigured or fault
FUDiff greater than 50c check isolation valves are open
Fault DescriptionSystem Behaviour
Overheat lockoutBleed radiators, refill system to 1.0 bar, check that radiator and boiler valves are open and reset boiler. If fault continues book an engineer.
Ignition lockoutCheck gas appliances work and restart boiler.
Too many restarts5 starts within 15 minutes. Turn power on and off.
Flame on before gas onFalse flame lockout.
Water pressureWith boiler off and system cold fill system to 1.0 bar and bleed radiators if fault continues contact an installer.
Fault DescriptionSystem Behaviour
Too many resets5 restarts within 15 minutes
Flame on before gas valve onFlame on before gas valve is on
Flow thermistor faultFlow thermistor error
Low mains voltageLess than 185v to boiler then check voltage at boiler mains in if mains voltage is okay pump needs replacing
Low water pressureLow water pressure
Flow return reversedCheck if the flow thermistor is correctly clipped to pipe. If not, replace flow thermistor.
Printed circuit board (PCB) recently replacedReset boiler
Pump rotor blockedUnblock pump
Flow temperature setpoint cannot be increased to 80cCheck flow and return thermistors securely clamped to pipes check flow and return thermistor
Fault DescriptionCause
Thermal fuse lockoutReset the boiler
Too many boiler resets5 resets within 15 minutes. Turn power off and on.
Printed circuit board (PCB) replaced incorrectlyEnsure the boiler chip card (BCC) is fitted correctly.
Low mains voltageLess than 160V to boiler. Contact electricity provider.
Low water pressureIncrease system pressure to 1.5 bar
Flow/Return reversedCheck if flow thermistor is correctly clipped to pipe. Replace flow thermistor.
Printed circuit board (PCB) replacedReset the boiler
No connection to primary printed circuit board (PCB)Unblock pump
Pump rotor blockedNo connection to primary printed circuit board (PCB)
Flow temperature setpoint cannot be increased to 80ºCEnsure flow temperature is not limited within installer mode
Pump runs during the nightEnsure system frost protection temperature setpoint isn’t set too high
Has the printed circuit board (PCB) just been replaced?Reset the boiler
Are the boiler, central heating and hot water systems filled with water? Are all isolation valves and radiator valves open?Fill and vent the system and open all isolation valves, then reset the boiler
Is the Flow/Return differential across the boiler in excess of 30cCheck the flow and return thermistors
Check that the pump is rotating freely.Replace the pump, then reset the boiler
If the boiler is reset, does it ignite for a short time and then extinguish?Check the detection electrode and associated harness for continuity, visual condition and position. Check if the condensate pipe is blocked.
Is the gas pressure avaliable at the boiler > 18mBarCheck gas supply and rectify fault
Is 215Vdc avaliable at the gas valve during ignition?Check wiring from gas valve to printed circuit board (PCB) and replace if necessary, otherwise replace the main PCB
Unplug the gas valve – is the resistance between the pins between 1kW and 10kW?Replace gas valve

Vaillant Boiler Error Codes

Fault CodePossible CauseMeaning
F.00NTC FaultsThis means that your Flow NTC (Negative Temperature Coefficient Thermistor) cable is either defective or broken and needs to be replaced
F.01The Flow NTC (Negative Temperature Coefficient Thermistor) cable is either defective or broken and needs to be replaced
F.10
F.11
F.13
F.20Boiler has exceeded the maximum temperature and needs to cool down
F.22Dry fire / Low water in system / OverheatThis means that there’s either no water in your system, you have a defective pump or the pump lead is defective
F.24Low water / Pump Failure / BlockagePump could be obstructed, running at low capacity, could be air trapped or the pressure might be too low.
F.28Either insufficient gas in the system, a defective electrode, ignition lead or electronic ignitor
F.29Flame extinguishedFlame or pilot light has gone out – check flue duct or gas supply.
F.60Gas valve control defectiveCable loom (connects gas valve) might have short circuited, gas valve assembly defective or electronic control system issue.
F.61Gas valve control defectiveCable loom (connects gas valve) might have short circuited, gas valve assembly defective or electronic control system issue.
F.62Defective gas valve closure mechanismBoiler has exceeded the maximum temperature and needs to cool down
F.63EEPROM (Electrically Erasable Programmable Read-Only Memory) errorElectronic fault.
F.64Electronic system or sensor faultFlow or back flow NTC has short circuited, or an electronic fault
F.65Electronic system temperature too highThis can happen because of an external heat source or an electrical fault
F.67Electronic fault in the flame system
Fault CodePossible Cause
F.1Lack of gas, a fault with the ignition or flue – may need to adjust the gas valve or replace a defective electrode lead.
F.4Ignition fault.
F.5The system has suffered a fault due to overheating.
F.6Your flow NTC has developed a fault.
F.17Check the polarity of your system.
F.24Pump-related faults – the pump could have failed, it may have over run or there could be an issue with the airlock
Fault CodePossible Cause
F.00, .04, .05, .10, .14, .15All of these are NTC faults, and are best resolved by first changing all NTC to make diagnosis earlier.
F.21The pilot flame has failed.
F.22There is insufficient water in your system.
F.11A blockage in the appliance is preventing the system from flowing as it should.
F.12A blockage in the appliance is affecting the system’s pressure.
F.13The appliance is blocked because of a water deficiency.
Fault CodePossible Cause
S.OHeating issue, no heat demand
S.1Fan start-up error
S.2Pump flow error
S.3Heating mode error – ignition problem
S.4Heat mode – burner on error
S.6Heating mode – fan overrun error
S.7Heating mode – pump overrun error
S.8Heating remaining cut off for XX amount of time
S.31No heat demand summer operating mode
S.34Heating mode frost protection error
S.20Hot water requirement error
S.22Hot water handling pump flow error
S.24Hot water operation burner is on
S.85Service message quantity of circulation water
Fault CodePossible Cause
F.00 / F.0Flow temperature sensor interruption
F.01 / F.1Return temperature sensor interruption
F.10Flow NTC short circuit
F.11Return NTC short circuit
F.20Safety switch off temperature limiter
F.22Safety switch off low water pressure
F.23Safety switch off temperature difference too great
F.24Safety switch off temperature is rising to fast
F.25Safety switch off flue gas temperature too high
F.26Error with gas valve – possible no function
F.27Safety switch off flame simulation
F.28Failure during start up – ignition unsuccessful to start
F.29Failure during operation – re-ignition unsuccessful
F.32Fan error
F.49eBUS error – possible short circuit
F.61Error with gas valve regulation
F.62Error with gas valve – switch off delay
F.63EEPROM error
F.64Electronics / NTC error
F.65Electronic temperature error could be overheating due to external influences
F.67Electronics flame signal error
F.68Unstable flame signal error air in gas
F.70Invalid device specific number (DSN)
F.71Flow NTC error – flow temperature sensor signal constant value
F.72Flow return NTC error – temperature difference too great
F.73Water pressure sensor signal in the wrong range, it is too low
F.74Water pressure sensor signal outside correct range, the sensor signal is too high
F.75Error with pressure – no pressure change detection when starting the pump
F.76Overheating protection on – primary heat exchanger has responded
F.77Flue non return flap condensate pump error
F.78Interruption to DHW outlet sensor at external controller
F.83Flow and or return temperature sensor error
F.84Error with flow/return temperature sensor temperature changing error
F.85Error with flow and return temperature, sensor incorrectly fitted
CONNECTIONNo communication with the PCB
Fault CodePossible Cause
S.00Heating mode error – no heat demand
S.01Heating mode fan start-up
S.02Heating mode error – water pump running
S.03Heating mode – ignition sequence error
S.04Heating mode – burner ignited
S.06Heating mode – fan overrun error
S.07Heating mode – pump overrun error
S.08Heating remaining cut off time xx minutes
S.10Hot water demand via impeller sensor
S.11DHW mode fan start up error
S13DHW mode ignition error
S.14Hot water demand via fan sensor error
S.15DHW mode pump and fan overrun
S.16DHW mode – fan overrun error
S.17DHW mode – pump overrun error
S.20DHW mode – burner on error
S.21DHW mode – fan start up error
S.22DHW demand – error pump running
S.23DHW ignition error
S.24DHW mode – burner error
S.25DHW mode – pump or fan overrun error
S.26DHW mode – fan overrun
S.27DHW mode – pump overrun
S.28Hot water burner anti-cycling time
S.30Room thermostat is blocking heating mode
S.31No heat demand boiler in summer operating mode
S.32Waiting period because of fan speed deviation
S.34Heating mode frost protection error
S.39Burner off contact has been triggered this could be because of contact thermostat or condensate pump
S.40Comfort safety mode active
S.41Water pressure > 2.8 bar
S.42Flue non return flap return signal blocks burner operation
S.46Comfort safety mode flame loss at minimum load
S.53Boiler is in waiting period of modulation f block function due to water shortage
S.54Boiler is in waiting period of operation, blocking function as a result
S.57Waiting period comfort safety mode
S.58Modulation limitation due to noise / wind error
S.61Gas family check unsuccessful
Fault CodePossible Cause
S.20Warnstar demand
S.21Fan running
S.22Pump running
S.23Ignition sequence
S.24Burner ignited
S.25Fan and water pump running
S.26Fan overrun
S.27Pump overrun
S.28Anti-cycling mode
S.30No heating demand from external controls
S.31Central heating thermostat knob turned off
S.32Heat exchanger antifreeze active as fan speed variation is too high
S.34Anti-frost mode is active
S.36Not heating demand form low voltage
S.41Water pressure greater than 2.9 bar
S.42Response from accessory module or defective condensate pump is blocking burner operation
S.53Appliance is within the waiting period of the block operation function due to water shortage
S.54Appliance is within the waiting period of the block operation due to water shortage
S.96Return sensor error
S.98Flow return sensor check is running demand is block
D.0Heating part load error
D.1Water pump overrun – time for heat mode
D.2Max burner anti-cycling period at 20c flow temperature
D.3Hot water flow temperature reading
D.4Current temperature for warm stat sensor
D.7Warm start temperature target value
D.8External controls heat demand
D.9Flow target temperature from external analogue regulator terminal
D.10Status internal heating pump error
D,11Status external heating pump error
D.12Cylinder charging pump via accessory module
D.13Hot water circulation pump
D.22Hot water demand
D.23Summer/Winter function
D.25Hot water activation via ebus control
D.30Control signal for both gas valves
D.33Fan speed target value
D.34Fan speed actual value
D.36Hot water flow sensor
D.40Flow temperature target value
D.41Return temperature actual value
D.44Digitised ionisation potential error
D.47Outside temperature with weather compensator – Vaillant controller only
D.76Remaining burner anti-cycling time in min
D.90Digital regulator status
D.91DCF status with connected external probe
D.97Activation of the second diagnostic level
D.17Heating glow return regulation
D.18Pump mode return
D.19Operating modes of the two speed heating pump
D.20Maximum set value for target cylinder
D.27Switching accessory relay 1
D.28Switching accessory relay 2
D.50Offset for minimum speed
D.51Offset for maximum speed
D.58Activation of solar reheating
D.60Number of safety temperature cut off
D.61Number of unsuccessful lockouts
D.64Average ignition times
D.65Maximum ignition time
D.68Unsuccessful ignitions in the first attempt
D.69Unsuccessful ignition for the second time
D.70Set diverter valve position
D.71Maximum setting of heater control knob
D.72Pump overrun time after warm start
D.73Off set for warm start target value
D.75Maximum charging time for a storage without own controller
D.77Limitation of cylinder charging in output in kW
D.78Limitation of cylinder charging temperature in c
D.80Operating hours heating
D.81Operating hours hot water generation
D.82Burner start up in heating mode
D.83Burner start up in hot water mode
D.84Maintenance indicator – number of hours until the next maintenance
D.93DSN appliance variant setting
D.96Factory setting
Fault CodePossible Cause
P.00The heating circuit and hot water circuit are purged
P.01Maximum load test program error
P.02Minimum load test program
P.06Filling mode test program
Fault CodePossible Cause
D.0Heating part load error
D.1Water pump overrun – time for heat mode
D.2Max burner anti-cycling period at 20c flow temperature
D.3Hot water flow temperature reading
D.4Current temperature for warm stat sensor
D.5Set value of flow temperature or target value of return
D.7Warm start temperature target value
D.8External controls heat demand
D.9Flow target temperature from external analogue regulator terminal
D.10Status internal heating pump error
D,11Status external heating pump error
D.12Cylinder charging pump via accessory module
D.13Hot water circulation pump
D.15Pump speed actual value
D.22Hot water demand
D.23Summer/Winter function
D.24Not relevant
D.25Hot water activation via eBus control
D.30Control signal for both gas valves
D.33Fan speed target value
D.34Fan speed actual value
D.35Not relevant
D.40Flow temperature target value
D.41Return temperature actual value
D.44Digitised ionisation – potential error
D.47Outside temperature with weather compensator – Vaillant controller only
D.76Remaining burner anti-cycling time in min
D.90Digital regulator status
D.91DCF status with connected external probe
D.97Activation of the second diagnostic level
D.98Telephone a heating engineer
D.14Pump speed target value
D.17Heating flow return regulation
D.18Pump operating mode
D.20Maximum set value for target cylinder
D.26Additional relay control ecoTec
D.27Switching accessory relay 1
D.28Switching accessory relay 2
D.50Offset for minimum speed
D.51Offset for maximum speed
D.60Number of safety temperature cut offs
D.61Number of unsuccessful lockouts
D.64Average ignition times
D.65Maximum ignition time
D.67Remaining burner anti-cycling time
D.68Unsuccessful ignitions in the first attempt
D.69Unsuccessful ignition for the second time
D.70Set diverter valve position
D.71Maximum setting of heater control knob
D.72Pump overrun time after warm start
D.75Maximum charging time for a storage without own controller
D.77Limitation of cylinder charging in output in kW
D.78Limitation of cylinder charging temperature in celsius
D.80Operating hours heating
D.81Operating hours hot water generation
D.82Burner start up in heating mode
D.83Burner start up in hot water mode
D.84Maintenance indicator – number of hours until the next maintenance
D.93DSN appliance variant setting
D.96Factory setting

Worcester Boiler Error Codes

Fault DescriptionSystem Behaviour
226Service tool has been connected in the blocking error history menu
FD 231The power has been interrupted during a lockout
C7 214Fan does not run during the start up phase – fan harness connector needs checking
C6 215Fan speed too high – check the fan harness and connector
C7 216Fan speed too low – check the fan harness and connector
C7 217Fan has stopped during appliance operation
C1 264Fan stopped during operation
C4 273Continuous fan operation for the last 24 hours – appliance temporarily blocked
E2 222Flow temperature sensor shorted
E2 233Flow temperature sensor disconnected
E9 276Primary flow temperature exceeded 95°c
E2 350Flow temperature sensor shorted
E2 351Flow temperature sensor disconnected
FA 306Ionisation detected after the gas valve closed
EA 227No ionisation detected after ignition
F7 228Isioniation current detected before burner start
EA 229Loss of ionisation signal during operation
EA 261Heat control module (HCM) potentially defective – reset the appliance
9U 233Control box or heat control module (HCM) is defective or loose, the HCM needs to be checked
C4 237Control box or heat control module (HCM) is defective
F0 238Gas valve or control box error – gas valve coils need checking
F0 239Control box or the heat control module (HCM) is defective – the control box connections need checking
F0 242Control box or the heat control module (HCM) is defective – the HCM and control box connections need to be checked
B7 257Control box or the heat control module HCM) is defective- the HCM and control box connections need to be checked
F0 258Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
EH 258Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
F1 259Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
F0 262Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
F1 263Control box or the heat control module (HCM) is defective – HCM or control box connections need to be checked
F0 272Control box or the heat control module (HCM) is defective – control box and connections need checking or HCM might not be inserted properly and need replacing
F0 280Control box or the heat control module (HCM) is defective – control box and connections need checking or HCM might not be inserted properly and need replacing
F0 290Control box is defective – HCM needs checking as it might not be inserted properly or need replacing
328Internal error with the mains voltage – frequency may be inconsistent
235Incompatible heat control module (HCM) software versions – control box needs latest software
356Low mains voltage – the voltage may be interrupted or inconsistent and needs checking
360Heat control module (HCM) invalid – the inserted HCM does not correspond with the control box
A8 362Low mains voltage – the voltage may be interrupted, inconsistent or heat control module (HCM) invalid
CC 800Outdoor sensor defect available when accessory outdoor sensor is connected
A1 281Pump stock or running dry
E9 224Flue or high limit thermostat activated
D4 341Primary flow temperature rising too fast
Fault DescriptionSystem Behaviour
208The boiler is in chimney sweep mode
200The boiler is in heating mode
201The boiler is in domestic hot water (DHW) mode
202The boiler is waiting – there was a heat demand from the on off or modulating control
203The boiler is on standby
204The boiler is waiting – the actual temperature is higher than the calculated or selected boiler temperature
212The temperature recorded by the flow temperature sensor or the safety sensor is rising too quickly
226Diagnosis tool was connected and is now locked out
260The flow temperature sensor is not detecting a rise in temperature following a burner start
265The boiler is waiting in response to a heat demand – the boiler regularly switches to partial load
268Component test phase
270The boiler is modulating upwards
283The boiler is preparing for a burner start – the fan and pump are activated
284The gas valve is switched
305The boiler is waiting for domestic hot water (DHW) operation to end
235The KIM (boiler identification module) is too new for the burner control unit
360The KIM that has been fitted is not compatible with the burner control unit
9A 361The burner control unit that has been fitted is not compatible with the KIM (boiler identification module)
9U 233The burner control unit or KIM (boiler identification module) is faulty
A3 317Short circuit in the flue gas temperature sensor contacts
B7 257The burner control unit or the KIM (boiler identification module) is faulty
C1 264No control signal or power supply to the fan during operation
C4 273The boiler was switched off for a maximum of 2 minutes because it had been operating continuously for more than 24 hours
C6 215The fan speed is too high
C6 216The fan speed is too low
C7 214The fan does not run during the start phase
C7 217The fan speed is irregular when starting up
CE 207Water pressure is too low
CE 266Pump test failed
D1 240The contacts of the boiler return temperature sensor have been short circuited
D1 241The contacts of the boiler return temperature sensor have been interrupted
D3 232The external switching contact has opened
D4 213The actual temperature recorded by the flow temperature sensor or return temperature sensor is rising too quickly
D4 271Actual temperature differential between flow and safety temperature sensor is too high
D4 286The boiler return temperature sensor has detected a return temperature higher than 105°c
E2 222Short circuit in the flow temperature sensor contacts
E2 223The flow temperature sensor contacts have been interrupted
E5 218The temperature captured by the flow temperature sensor exceeded 105°c
E9 210The temperature measured by the flue gas sensor is too high and is open
E9 219The safety temperature sensor has captured a temperature in excess of 105°C
E9 220The contacts for the safety temperature sensor have shorted or the safety temperature sensor has detected a temperature higher than 130°c
E9 224The contacts of the safety temperature sensor have been interrupted
E9 276The temperature flow sensor has measured a temperature in excess of 95°c
E9 277The safety temperature sensor has measured temperature in excess of 95°c
E9 285The boiler return temperature sensor has measured a temperature higher than 95°c
E9 318The flue gas temperature sensor contacts have been interrupted
EA 227An insufficient ionisation current was measured following ignition of the burner
EA 229The ionisation current detected by the system during the burning phase was insufficient
EA 234The contacts of the gas valve have been interrupted
EA 261The burner control unit is faulty
EA 269The ignition device has been activated for too long
F0 238The burner control unit KIM (boiler identification module) is faulty
F0 239The burner control unit KIM (boiler identification module) has an error. Cabling might have poor contact breaks and pinching or the plug and wiring of the burner control unit needs checking, also check the operating characteristics of the boiler by replacing the burner control unit.
F0 242, F0 243. F0 244. F0 245, F0 246. F0 247, F0 248, F0 249, F0 250, F0 251, F0 252, F0 253, F0 255, F0 259, F0 263, F0 267, F0 272The burner control unit (KIM) is faulty – the wiring of the burner control unit needs checking, also check the operating characteristics of the boiler by replacing the burner control unit.
F0 278The sensor test has failed – cabling and plug sensors need checking
F0 279The burner control unit, or KIM, is faulty – control unit may need replacing
F0 280The burner control unit is faulty
F0 287The burner control unit, or KIM, has an error
F0 290The burner control unit, or KIM, is faulty
F7 228An ionisation current was measured before the burner started
F7 328A brief power failure has occurred
FA 306An ionisation current was measured after the burner went out
FD 231The mains voltage was interrupted during an interlocking fault
EC 256The burner control unit has an error
EH 258The burner control unit is faulty – check the plug and wiring of the burner control unit.
H07The current water pressure is too low, limiting the performance in heat mode as well as domestic hot water (DHW) mode
HrEThe boiler keeps resetting
rEThe boiler resets
Fault DescriptionSystem Behaviour
Light offNo boiler demand
Light onHeating demand on boiler is OK
1 flash 5 seconds offNo ionisation detected after ignition
2 flashes 5 seconds offLoss of ionisation signal during operation
3 flashes 5 seconds offGas valve error
4 flashes 5 seconds offFirst safety timing error / ignition timing error
5 flashes 5 seconds offIonisation detected after burner stopped
Gas valve EV2 leak test failed
Gas valve EV1 leak test failed
Ionisation current detected before burner start
Gas valve error
Ionisation sensor shorted
4 flashes 5 second gap 1 long flashSensor test failed
4 flashes, 5 second gap, 2 long flashesSafety temperature too high
4 flashes, 5 second gap, 3 long flashesMax safety thermostat activated
4 flashes, 5 second gap, 4 long flashesReturn temperature too high
4 flashes, 5 second gap, 5 long flashesFlow temperature too high – supply sensor exceeded 110°c
1 long flash, 4 quick flashes, 5 second gap, 1 long flash, 4 quick flashesHeating control module (HCM) defective
2 long flashes, 4 quick flashes, 5 second gap, 2 long flashes, 4 quick flashesFan running too fast
Fan running too slow
No airflow after defined period of time
Fan not running
3 long flashes, 4 quick flashes, 5 second gap, 3 long flashes, 4 quick flashesMains voltage interrupted after locking error
4 long flashes, 4 quick flashes, 5 second gap, 4 long flash, 4 quick flashesInternal control board faults
5 long flashes, 4 quick flashes, 5 second gap, 5 long flash, 4 quick flashesAll other miscellaneous faults – reset the boiler by turning the control knob anti-clockwise to the reset position
Fault DescriptionSystem Behaviour
No lightNo power at control board
Light onAppliance on but not operating during demand
Slow flash ( mostly off flashes on)Ignition lockout
Slow flash ( mostly on flashes off)Flue overheat or heat exchanger overheat
Fast flashVolatile lockout sensor fan or code plug
2 pulsesCheck service mode switch is in minimum position
5 pulsesCheck service mode switch is in max position
Fault DescriptionSystem Behaviour
200 OBoiler in heating mode
201 OBoiler in hot water mode
202 OBoiler in anti-cycle mode
203 0Boiler in standby – no heat energy demand
204 OCurrent primary water temperature higher than set value
208 0Chimney sweep demand
224 VSafety temperature limiter has tripped – top-up water until the reset pressure is reached
227 VNo flame signal after ignition burner control unit could need replacing
228 VFlame signal without flame present – air/gas ratio control valve may need replacing as might the ionisation cable
305 0Boiler in hot water anti-cycle mode
306 VFlame signal after closing the fuel supply – the air/gas ratio control valve might need replacing
360 VIncompatible code plug – check if a correct code plug is installed and exchange or reconnect code plug
815 W/BLow loss header temperature sensor faulty – check the sensor port or check the differential sensor for incorrect installation position or breakage
1010 ONo BUS communication cable, EMS-Bus isn’t connected or damaged – connect the cable for the EMS-Bus or replace the damaged cable exchange fuse
1017 WWater pressure too low – the water needs topping up and the vent system or pressure sensor may need replacing
1021 BHot water temperature sensor is defective – the plug to the hot water temperature sensor may not be connected
1022 BHot water storage temperature sensor is defective – connect the plug to the hot water temperature sensor correctly, mount the hot water temperature sensor correctly or replace the hot water temperature sensor
1037 WOutside temperature sensor is defective – check the connecting lead
1065 BPressure sensor defective or not connected – check pressure sensor connection as it may need replacing
1068 WOutside temperature sensor defective – check the connecting lead
1073 WShort circuit of the flow temperature sensor – the temperature sensor may need replacing
1074 WNo signal from the flow temperature sensor available – connect the plug to the flow temperature sensor correctly or temperature sensor could need replacing
1075 WShort circuit of the temperature sensor at the heating block – temperature sensor may need replacing
1076 WNo signal from the temperature sensor at the heating block available – replace the temperature sensor, the connecting lead or the control unit
2920 VError with the flame monitoring
2924 VNo feedback from the modulating gas valve. The gas valve relay is defective – press the reset button and apply burner start, wait to see if fault reoccurs, if it does the gas valve needs replacing
2925 VFeedback from the modulating gas valve is too low
2927 BFlame failed during burner operation. Open the main shut off valve, shut down the appliance and check gas line, replace the ionisation electrode, set burner correctly and minimum rated load, check the integrity flue system and if the interconnected room air supply is too small, or the size of the ventilation opening is too small, clean the heating block on the flue gas side or replace the control unit/burner control unit
2946 VIncorrect code plug detected – the code plug needs replacing
2948 BNo flame signal. With low output the burner starts automatically after cleaning. If the fault occurs repeatedly, the setting of the CO2 valves need checking
2950 BNo flame signal. Following starting procedure the burner starts automatically. After cleaning set the correct gas / air ratio correctly
2963 BSignal from flow and heat exchanger temperature sensor outside the permissible range – the connecting lead needs connecting correctly
2964 BFlow rate in heat exchanger is too low
2965 BFlow temperature too high
2966 BFlow temperature rise in heat exchanger too rapid
2967 BFlow / heat exchanger temperature sensor differential too great
2970 BPressure drop in heating system too rapid
2971 BSystem pressure too low – the heating system needs venting or water needs topping up until the preset pressure is reached. Replace the cable to the pressure sensor replace the pressure sensor