Baxi
Fault Codes

Listed below are the common Baxi fault codes as described by the boiler manufacturer along with a possible cause.

Baxi Platinum Error Codes

Fault CodePossible Cause
E20 Central heating NTC error
E28 Error with the NTC (Negative Temperature Coefficient) flue, air pressure switch or blocked flue or condensate
E50 Hot water NTC (Negative Temperature Coefficient) error
E110 Thermostat operated safety
E119 Water pressure switch error – not operated.
E125 Primary circuit error circulation fault
E130 Flue NTC (Negative Temperature Coefficient) operation error
E133 Gas supply error or flame failure
E160 Fan or fan wiring error
E193 Pre-circulation error

Baxi EcoBlue Error Codes

Fault CodePossible Cause
110 Overheated – try bleeding your radiators
117 Water pressure too high
118 Water pressure too low
125 Water circulation fault
133 Safety time to establish flame exceeded
E10 Outdoor sensor error
E20 Central heating thermistor sensor fault
E28 Flue thermistor fault
E54 Domestic hot water (DHW) flow sensor fault
E78 Water pressure sensor fault
E100 Internal clock time error on printed circuit board (PCB)
E109 Poor circulation
110 Overheat – try bleeding your radiators
111 Maximum limit of flow temperature
117 Water pressure too high
118 Water pressure too low
119 System pressure too low
125 Water circulation fault
127 Legionella (cause of Legionnaires’ disease) protection temperature not reached
128 Loss of flame during operation
133 Safety time to establish flame exceeded
153 Forced reset unit unlocked
160 Fan fault
162 Air pressure switch error
164 Pressure Sensor Error (UK) – Heating flow switch error (Ireland)
166 Air pressure switch fault
270 Dry fire
432 Earth connector error
433 Heat exchanger temperature exceeded (greater than 95 degrees)

EcoBlue Advance / Ecoblue Regular Gas Boiler Flashing Light                     Fault Codes

Fault CodePossible Cause
1 green flash Boiler temperature reached. No action required.
3 green flashes Temporary flame loss. Boiler will self reset, if fault continues you will see 3 red flashes.
4 green flashes Communication error between printed circuit board (PCB) and control. Temporary error, will self reset.
5 green flashes Parameter error on printed circuit board (PCB). Temporary error, will self reset
6 green flashes Miscellaneous error. Temporary error, will self reset.
1 red flash Sensor error, temperature fault or flow fault.
2 red flashes Boiler overheat tripped
3 red flashes Ignition fault. Boiler has attempted to light 5 times and failed.
4 red flashes Fan fault
5 red flashes Parameter storage unit (PSU) error.
6 red flashes Miscellaneous error.

Baxi Duo-tec/Megaflo Error Codes

Fault CodePossible Cause
E10 Outdoor sensor fault
E20 Central heating thermistor sensor error
E28 Flue thermistor error
E110 Boiler overheat error
E119 low water pressure error
E125 Primary water circulation error
E131 Flue overheat lockout error
E133 Ignition error
E160 / E161 Fan error
E164 Pressure sensor fault
E167 Printed circuit board (PCB) error
E168 Printed circuit board (PCB) lockout error
E193 Circulation error

Baxi 200 / 400 Combi Gas Boiler Error Codes

Fault CodePossible Cause
H.01 – .00 Loss of communication between gas valve and boiler board. Possible fault in air/gas unit or loose connection to gas valve.
H.01 – .05 Difference between the flow and return temperature is too high, sensor error or insufficient circulation.
H.01 – .08 Sensor fault, flow temperature increasing too fast in heating mode or insufficient circulation.
H.01 – .14 Maximum flow temperature value exceeded or insufficient circulation – temporary fault.
H.01 – .18 No water circulation, insufficient circulation or sensor error.
H.01 – .21 Temporary error – flow temperature increasing too fast in domestic hot water (DHW) mode, insufficient circulation or sensor error.
H.02 – .02 Temporary error – no input of parameters C1/C2. Printed circuit board (PCB) not configured.
H.02 – .03 Temporary error- incorrect configuration settings C1/C2.
H.02 – .04 Temporary error- parameter fault. Incorrect parameters.
H.02 – .06 Temporary error caused by system water pressure, water leak on boiler, water leak on system.
H.03 -.00 Temporary error with communication, negative temperature coefficient thermostat (NTC) or flue sensor. Sensor could also be unconnected or have a bad connection.
H.03 – .01 Communication error with the printed circuit board (PCB)
H.03 – .02 Flame error – no flame during operation.
E.00 – .04 Return temperature sensor open-circuit. Sensor not or badly connected.
E.00 – .05 Return temperature sensor short-circuit. Sensor not connected or badly connected.
E.01 – .02 Temperature measured by return sensor greater than flow sensor.
E.01 – .04 Loss of flame detected 5 times in 24 hours (with burner on).
E.01 – .11 Incorrect fan speed – external draught over the boiler or defective gas/air unit.
E.01 – .12 Requires reset – temperature measured by return sensor greater than flow temperature.
E.01 – .17 Reset the boiler – no circulation, sensor fault either not connected or has a bad connection.
E.01 – .20 Maximum flue gas temperature reached. No circulation or sensor fault.
E.02 – .00 Reset button has been pressed.
E.02 – .07 No or low system water pressure. system pressure less than 0.5bar
E.02 – .16 Permanent fault caused by channel service unit (CSU) time-out or printed circuit board (PCB) damage.
E.02 – .17 Loss of communication between gas valve and boiler printed circuit board (PCB) or fault in air/gas unit.
E.02 – .19 Jumper 1 changed – check position of jumper 1.
E.02 – .20 Jumper 2 changed – check position of jumper 2.
E.02 – .21 Jumper 3 changed – check position of jumper 3.
E.02 – .47 Wiring to external device error.
E.02 – .48 Configuration to external device unsuccessful – check pairing to external device.
E.04 – .00 Gas valve error – gas valve not detected.
E.04 – .01 Flow temperature sensor short-circuited. Sensor not or badly connected, bad connection or sensor fault.
E.04 – .02 Permanent fault. Flow temperature sensor open-circuited, sensor not or badly connected, bad connection or sensor fault.
E.04 – .03 Permanent fault. Critical flow temperature reached, non-existent or insufficient circulation.
E.04 – .04 Permanent fault. Flue temperature sensor short-circuited, sensor not or badly connected, bad connection or sensor fault.
E.04 – .05 Permanent fault. Flue temperature sensor short-circuited, sensor not or badly connected, bad connection or sensor fault.
E.04 – .06 Permanent fault. Critical flue gas temperature value reached, no circulation or sensor fault.
E.04 – .08 Permanent fault. Maximum safe temperature value reached, safety thermostat open-circuited, no circulation, sensor not or badly connected, bad connection or sensor fault.
E.04 – .10 Failure to light (could be gas supply issue).
E.04 – .12 Permanent 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 – .13 Permanent fault. Fan rotor blocked, fan seized or wiring to fan damaged.
E.04 – .17 Permanent fault. Problem with gas valve or defective gas/air unit.

Baxi 600 Combi Gas Boiler Error Codes

Fault CodePossible Cause
E09 Gas valve connection cable.
E10 External probe fault.
E12 Differential water flow switch fault (still open).
E13 Differential water flow switch fault (still closed).
E15 Gas valve command fault.
E20 Central heating negative temperature coefficient (NTC) thermostat fault.
E28 Flue negative temperature coefficient (NTC) thermostat fault.
E40 Central heating return negative temperature coefficient (NTC) thermostat fault.
E50 Domestic 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/E87 No communication.
E109 Pre-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.
E118 Primary system water pressure too low (< 0.5 bar).
E125 Circulation fault (primary).
E128 Frequent flame failure (12 times).
E129 Safety error for frequently loss of flame with max correction during the ignition during Calibration Function.
E130 Flue thermostat sensor tripped (lockout)
E133 Failure to light (could be a gas supply issue)
E134 Elapsed time gas valve open without gas
(short request in a short period)
E135 Interruption of gas supply (internal error)
E154 Flow/return sensor temperature test.
E160 Fan or fan wiring fault.
E163 Domestic hot water (DHW) negative temperature coefficient (NTC) thermostat sensor fault (s.c.) or DHW NTC sensor fault (o.c.).
E270 Circulation fault (dry fire).
E317 Wrong power supply electrical frequency (Hz).
E321 Hot water negative temperature coefficient (NTC) fault.
E384 False flame.
E385 Under voltage.
E430 Water pressure temporary test.
E430 + Flame ‘crossed’ Water pressure test failed.

Baxi MainEco Error Codes

Fault CodePossible Cause
1 Green Flash Boiler temperature reached – no action required
3 Green Flashes Temporary flame loss – this is a temporary error, the system should reset on its own
4 Green Flashes Communication error between printed circuit board (PCB) and Control – this is a temporary error, the system should reset on its own
5 Green Flashes Parameter 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 Flashes Miscellaneous error
1 Red Flash Sensor error, sensor fault, temperature fault or flow fault – this is a temporary error, the system should reset on it’s own.
2 Red Flashes Boiler overheat tripped
3 Red Flashes Ignition fault. Boiler has attempted to light 5 times and failed
4 Red Flashes Fan Fault
5 Red Flashes Parameter storage unit (PSU) error
6 Red Flashes Miscellaneous

Baxi Avanta Range Error Codes

Fault CodePossible Cause
E0 Temperature sensor fault
E1 Overheated – try bleeding your radiators
E2 Poor circulation – try bleeding your radiators
E3 Printed circuit board (PCB) fault
E4 Ignition failure – try bleeding your radiators
E10 Poor/No circulation
E12 Printed circuit board (PCB) Fault
E13 Heat exchanger thermal fuse tripped
E83 / 84 / 85 / 86 / 87 Fan fault normally E8

Baxi GA Range Error Codes

Fault CodePossible Cause
E53 Poor combustion – flue terminal may be blocked
E110 Overheated – try bleeding your radiators
E117 System water pressure high – try bleeding water from your radiators
E118 System water pressure low 
E125 Overheat – try bleeding your radiators
E133 Gas supply fault
E4 Ignition failure
E09 Gas valve wiring fault
E10 Outdoor sensor error
E15 Gas valve connection fault
E20 Central heating thermistor sensor fault
E28 Flue thermistor fault
E40 Central heating return thermistor fault
E53 Flue obstruction
E55 Calibration required
E78 Water pressure sensor fault
E92 Combustion test alarm during auto-setting
E109 Poor circulation
E110 Boiler overheat tripped
E117 System pressure high (>2.9 Bar)
E118 System pressure low(< 0.5bar)
E125 Primary water circulation fault
E128 Loss of flame during operation
E129 Loss of flame during calibration
E133 Ignition fault
E135 Internal error
E154 Primary flow fault
E160 Fan fault
E270 Dry fire
E317 Wrong power supply (Hz)
E321 Not water thermistor fault
E384 Flame detected when gas valve off
E385 Low voltage (less than 195v)

Baxi Solo Error Codes

Fault CodePossible Cause
FLASH FLASH ON Fan error
FLASH OFF FLASH Voltage less than 180V
FLASH OFF ON Overheat lockout
FLASH ON FLASH Printed circuit board (PCB) error
FLASH ON ON Printed circuit board (PCB) fault
OFF OFF OFF No power
ON FLASH FLASH Circulation error or dry fire
ON FLASH ON Thermistor error
ON OFF FLASH Live and neutral reversed error
ON OFF ON Ignition lockout error
ON ON FLASH Printed circuit board (PCB) error
ON ON ON Low voltage wiring harness error

Error Code E133 and E28

If you’re seeing either of these two error codes on your Baxi boiler, this is due to your condensate pipe being frozen. In the cold winter months this can happen easily as the condensate pipe runs outside. You can fix this issue by thawing out the pipe (if you feel confident to).