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Baxi Boiler Error Codes

Error codes are shown on Baxi boilers to indicate that the product has an issue. Below you will find a list of Baxi boiler error codes for all current Baxi products and we’ve even given you guidance (where available) on the action you need to take.

Error CodePossible Fault
H.01 – .00Temporary Fault – Temporary loss of communication between gas valve and boiler board. Fault in air/gas unit.

Loose connection to gas valve.

H.01 – .05Temporary Fault – Maximum difference between the flow and return temperature exceeded. Non-existent or insufficient circulation. Sensor error.
H.01 – .08Temporary Fault – Flow temperature increasing too fast in heating mode. Non-existent or insufficient circulation.
Sensor error.
H.01 – .14Temporary Fault – Maximum flow temperature value exceeded. Non-existent or insufficient circulation. Non-existent or insufficient circulation.
H.01 – .18Temporary Fault – No circulation of water. Non-existent or insufficient circulation. Sensor error.
H.01 – .21Temporary Fault – Flow temperature increasing too fast in DHW mode. Non-existent or insufficient circulation. Sensor error.
H.02 – .02Temporary Fault – No input of parameters C1/C2. PCB not configured.
H.02 – .03Temporary Fault- Incorrect configuration settings C1/C2.
H.02 – .04Temporary Fault – Parameter error. Incorrect parameters.
H.02 – .06Temporary Fault – System water pressure. Water leak on boiler. Water leak on system.
H.03 -.00Temporary Fault – Communication error with NTC flue sensor. Sensor not, or badly connected. Bad connection. Sensor fault.
H.03 -.01Temporary Fault – Communication error with the HMI PCB. HMI not connected.
H.03 -.02Temporary Fault – No flame during operation. No ionization current.
E.00 – .04Permanent Fault – Return temperature sensor open-circuit. Sensor not or badly connected. Bad connection. Sensor fault.
E.00 – .05Permanent Fault – Return temperature sensor open-circuit. Sensor not or badly connected. Bad connection. Sensor fault.
E.01 – .02Permanent Fault – Temperature measured by return sensor greater than flow sensor. Bad connection. Sensor fault. Sensor not or badly connected.
E.01 – .04Permanent Fault – Loss of flame detected 5 times in 24 hours (With burner on). No ionization current.
E.01 – .11Permanent Fault Requiring Reset – Incorrect fan speed. External draught over the boiler. Defective gas/air unit.
E.01 – .12Permanent Fault Requiring Reset – Temperature measured by return sensor greater than flow temperature.
E.01 – .17Permanent Fault Requiring Reset – No circulation. Sensor not or badly connected. Sensor fault.
E.01 – .20Permanent Fault – Maximum flue gas temperature value reached (>140 Deg C). No circulation. Sensor fault.
E.02 – .00Permanent Fault – Boiler reset in progress. Reset button has been pressed.
E.02 – .07No or low system water pressure. Low system pressure (less than 0.5bar) boiler will not function.
E.02 – .16Permanent Fault – On board CSU time-out. Check PCB for damage.
E.02 – .17Permanent Fault – Permanent loss of communication between gas valve and boiler PCB. Fault in air/gas unit. Loose connection to gas valve.
E.02 – .19Permanent Fault – Jumper 1 changed. Check position of jumper 1.
E.02 – .20Permanent Fault – Jumper 2 changed. Check position of jumper 2.
E.02 – .21Permanent Fault – Jumper 3 changed. Check position of jumper 3.
E.02 – .47Permanent Fault – Connection to external device unsuccessful. Check wiring to external device.
E.02 – .48Permanent Fault – Configuration to external device unsuccessful. Check pairing to external.
E.04 – .00Permanent Fault – Gas valve fault. Gas valve not detected.
E.04 – .01Permanent Fault – Flow temperature sensor short-circuited. Sensor not or badly connected. Bad connection. Sensor fault.
E.04 – .02Permanent Fault – Flow temperature sensor open-circuited. Sensor not or badly connected. Bad connection. 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. Sensor fault.
E.04 – .05Permanent Fault – Flue temperature sensor open-circuited. Sensor not or badly connected. Bad connection. Sensor fault.
E.04 – .06Permanent Fault – Critical flue gas temperature value reached. No circulation. Sensor fault.
E.04 – .08Permanent Fault – Maximum safe temperature value reached. (Safety thermostat open-circuited). No circulation. Sensor not or badly connected. Bad connection. 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). Defective gas/air unit.
E.04 – .13Permanent Fault – Fan rotor blocked. Fan seized. Wiring to fan damaged.
E.04 – .17Permanent Fault – Problem with gas valve. Defective gas/air unit.
Error CodePossible Fault
E20Central heating NTC fault
E28Flue NTC fault, air pressue switch fault, blocked flue, blocked condensate or wiring fault.
E50Hot water NTC fault
E110E110 safety thermostat operated
E119Water pressure switch not operated
E125Circulation fault (primary circuit)
E130Flue NTC operated
E133Interruption of gas supply or flame failure
E160Fan or fan wiring Fault
E193Pre-circulation fault
Error CodePossible Fault
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 NTC fault.
E28Flue NTC fault.
E40Central heating return NTC fault.
E50DHW NTC sensor fault (tank boiler) (s.c.) OR DHW NTC sensor fault (tank boiler) (o.c.).
E83 / E84 / E85 / E86 / E87No communication.
E109Pre-circulation fault.
E110i) Boiler max temperature exceeded for gradient (probable pump jammed or air in the circuit). OR ii) Boiler max temperature exceeded for overtemperature (probable pump jammed or air in the circuit). OR iii) Safety thermostat sensor tripped.
E118Primary system water pressure too low (< 0.5 bar).
E125Circulation fault (primary).
E128Frequent flame failure (12 times).
E129Safety error for frequent 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 NTC sensor fault (s.c.) OR Domestic Hot Water NTC sensor fault (o.c.).
E270Circulation fault (dry fire).
E317Wrong power supply electrical frequency (Hz).
E321Hot water NTC fault.
E384False flame.
E385Under voltage.
E430Water pressure temporary test.
E430 + Flame ‘crossed’Water pressure test failed.
Error CodePossible Fault
1 flash greenMaximum flow temperature exceeded, Flow temperature rise rate too high, Excessive difference between, flow and return temperature
2 flashes greenBL terminals on User Interaction, Controller are open circuit
3 flashes greenNo flame detected during operation
4 flashes greenBad connection or wiring fault, Internal communication fault
5 flashes greenParameter error or faulty PU, Configuration error or PCB fault
6 flashes greenPossible fault. Internal fault in combustion control unit
1 flash redBad connection to flow or return temperature sensor
2 flashes redOver-temperature thermostat on heat exchanger activated, No water flow through heat exchanger, PCB over-temperature condition, Flue fault resulting in recirculation or activation of air pressure switch (if fitted)
3 flashes redNo ignition, No flame detected following ignition, False flame signal detected
4 flashes redFan calibration error, Fan failure
5 flashes redBad connection to PU, Parameter error or faulty PU
6 flashes redPossible fault. Bad connection or wiring fault, Parameter error
Error CodePossible Fault
E09Gas valve connection cable
E15Gas valve fault
E20Central heating NTC fault
E28Flue NTC fault
E40Central heating return NTC fault
E83Communication error
E109Pre-circulation fault
E110Safety thermostat operated
E118Primary system water pressure too low
E125Circulation fault (primary)
E128Flame failure
E130Flue NTC operated
E133Interruption of gas supply or flame failure
E135Interruption of gas supply (internal error)
E135Interruption of gas supply (internal error)
E154Flow/ return sensor temperature test
E160Fan or fan wiring fault
E270Circulation fault (Dry fire)
E321Hot water NTC fault
E384False flame
Error CodePossible Fault
E10Outdoor Sensor Error
E20Central Heating Thermistor Sensor Fault
E28Flue Thermistor Fault
E54HW Flow Sensor Fault
E78Water Pressure Sensor Fault
E100Internal Clock Time Error on PCB
E109Poor Circulation
110Overheat
111Maximum Limit of Flow Temperature
117Water pressure too high
118Water pressure too low
119System Pressure Low (<0.5 bar)
125Water circulation fault
127Legionella 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
164Heating flow switch error (Ireland) Pressure Sensor Error (UK)
166Air Pressure Switch Fault
270Dry Fire
432Earth connector error
433Heat exchanger temperature exceeded (greater than 95 degrees)
Error CodePossible Fault
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; Sensor Fault, 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 or PSU Error
6 Red flashesMiscellaneous error.
Error CodePossible Fault
E10Outdoor sensor error
E20Central Heating Thermistor Senor Fault
E28Flue Thermistor Fault
E110Boiler Overheat. Ensure radiators are bled of air
E119Low water pressure. Add water to the system via the filling loop
E125Primary Water Circulation Fault. Ensure radiators are bled of air
E131Flue overheat lock out. This may follow a power cut, try reset
E133Ignition fault – Check gas is turned on, if prepayment meter check there is credit. If all ok and E133 persists – contact Engineer to visit & investigate
E160/E161Fan Fault
E164Fan Fault
E167PCB Fault
E168PCB lock out
E193Circulation fault
Error CodePossible Fault
Flash Off FlashIncoming Voltage less than 180V
Flash Off OnOverheat lockout
Flash On FlashPCB fault
Flash On OnPCB fault
Off Off OffNo power supply
On Flash FlashNo circulation/dry fire
On Flash OnThermistor fault
On Off flashLive and neutral reversed
On Off OnIgnition lockout
On Off FlashPCB fault
On Off FlashLow voltage wiring harness fault
Error CodePossible 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)
Error CodePossible Fault
E1Boiler overheat tripped
E2Poor circulation
E3PCB fault
E4Ignition failure
E10Poor/No circulation
E12PCB Fault
E13Heat exchanger thermal fuse tripped
E83/84/85/86/87Fan fault normally E8

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