Baxi boiler error codes

Boilers are an essential part of our daily lives, providing us with hot water and heating our homes. Baxi boilers are one of the most popular brands in the UK and are known for their reliability and efficiency. However, like any mechanical device, Baxi boilers can encounter problems, and when they do, they display error codes to help diagnose the issue. Understanding these error codes can save you time and money, as you can identify the problem before calling a professional boiler repair service. In this blog post, we will explore the different Baxi boiler error codes and what they mean.

BAXI 200 COMBI / BAXI 400 COMBI Boiler Error/Fault Codes

Error Code	Possible Fault
H.01 – .00	Temporary Fault – Temporary loss of communication between the gas valve and boiler board. Fault in air/gas unit. Loose connection to the gas valve.
H.01 – .05	Temporary Fault – Maximum difference between the flow and return temperature exceeded. Non-existent or insufficient circulation. Sensor error.
H.01 – .08	Temporary Fault – Flow temperature increasing too fast in heating mode. Non-existent or insufficient circulation. Sensor error.
H.01 – .14	Temporary Fault – Maximum flow temperature value exceeded. Non-existent or insufficient circulation. Non-existent or insufficient circulation.
H.01 – .18	Temporary Fault – No circulation of water. Non-existent or insufficient circulation. Sensor error.
H.01 – .21	Temporary Fault – Flow temperature increasing too fast in DHW mode. Non-existent or insufficient circulation. Sensor error.
H.02 – .02	Temporary Fault – No input of parameters C1/C2. PCB not configured.
H.02 – .03	Temporary Fault– Incorrect configuration settings C1/C2.
H.02 – .04	Temporary Fault – Parameter error. Incorrect parameters.
H.02 – .06	Temporary Fault – System water pressure. Is a water leak in the boiler causing an emergency? Water leaks on the system.
H.03 -.00	Temporary Fault – Communication error with NTC flue sensor. Sensor not, or badly connected. Bad connection. Sensor fault.
H.03 -.01	Temporary Fault – Communication error with the HMI PCB. HMI is not connected.
H.03 -.02	Temporary Fault – No flame during operation. No ionization current.
E.00 – .04	Permanent Fault – Return temperature sensor open-circuit. Sensor not or badly connected. Bad connection. Sensor fault.
E.00 – .05	Permanent Fault – Return temperature sensor open-circuit. Sensor not or badly connected. Bad connection. Sensor fault.
E.01 – .02	Permanent Fault – Temperature measured by return sensor greater than flow sensor. Bad connection. Sensor fault. Sensor not or badly connected.
E.01 – .04	Permanent Fault – Loss of flame detected 5 times in 24 hours (With burner on). No ionization current.
E.01 – .11	Permanent Fault Requiring Reset – Incorrect fan speed. External draught over the boiler. Defective gas/air unit.
E.01 – .12	Permanent Fault Requiring Reset – Temperature measured by return sensor greater than flow temperature.
E.01 – .17	Permanent Fault Requiring Reset – No circulation. Sensor not or badly connected. Sensor fault.
E.01 – .20	Permanent Fault – Maximum flue gas temperature value reached (>140 Deg C). No circulation. Sensor fault.
E.02 – .00	Permanent Fault – Boiler reset in progress. Reset button has been pressed.
E.02 – .07	No or low system water pressure. Low system pressure (less than 0.5bar) boiler will not function.
E.02 – .16	Permanent Fault – Onboard CSU time-out. Check PCB for damage.
E.02 – .17	Permanent Fault – Permanent loss of communication between the gas valve and boiler PCB. Fault in air/gas unit. Loose connection to the gas valve.
E.02 – .19	Permanent Fault – Jumper 1 changed. Check the position of jumper 1.
E.02 – .20	Permanent Fault – Jumper 2 changed. Check the position of jumper 2.
E.02 – .21	Permanent Fault – Jumper 3 changed. Check the position of jumper 3.
E.02 – .47	Permanent Fault – Connection to external device unsuccessful. Check wiring to external device.
E.02 – .48	Permanent Fault – Configuration to external device unsuccessful. Check pairing to external.
E.04 – .00	Permanent Fault – Gas valve fault. Gas valve not detected.
E.04 – .01	Permanent Fault – Flow temperature sensor short-circuited. Sensor not or badly connected. Bad connection. Sensor fault.
E.04 – .02	Permanent Fault – Flow temperature sensor open-circuited. Sensor not or badly connected. Bad connection. 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. Sensor fault.
E.04 – .05	Permanent Fault – Flue temperature sensor open-circuited. Sensor not or badly connected. Bad connection. Sensor fault.
E.04 – .06	Permanent Fault – Critical flue gas temperature value reached. No circulation. 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. 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 presents even though there is no flame. The burner remains very hot (CO2 is too high). Defective gas/air unit.
E.04 – .13	Permanent Fault – Fan rotor blocked. Fan seized. Wiring to fan damaged.
E.04 – .17	Permanent Fault – Problem with the gas valve. Defective gas/air unit.

BAXI 600 HEAT / MAIN ECO COMPACT HEAT Boiler Error/Fault Codes

Error Code	Possible Fault
1 flash green	Maximum flow temperature exceeded, Flow temperature rise rate too high, Excessive difference between, flow and return temperature
2 flashes green	BL terminals on User Interaction, Controller are open circuit
3 flashes green	No flame detected during operation
4 flashes green	Bad connection or wiring fault, Internal communication fault
5 flashes green	Parameter error or faulty PU, Configuration error or PCB fault
6 flashes green	Possible fault. Internal fault in combustion control unit
1 flash red	Bad connection to flow or return temperature sensor
2 flashes red	Over-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 red	No ignition, No flame detected following ignition, False flame signal detected
4 flashes red	Fan calibration error, Fan failure
5 flashes red	Bad connection to PU, Parameter error or faulty PU
6 flashes red	Possible fault. Bad connection or wiring fault, Parameter error

BAXI 600 SYSTEM / BAXI 800 SYSTEM / BAXI 600 LPG Boiler Error/Fault Codes

Error Code	Possible Fault
E09	Gas valve connection cable
E15	Gas valve fault
E20	Central heating NTC fault
E28	Flue NTC fault
E40	Central heating return NTC fault
E83	Communication error
E109	Pre-circulation fault
E110	Safety thermostat operated
E118	Primary system water pressure too low
E125	Circulation fault (primary)
E128	Flame failure
E130	Flue NTC operated
E133	Interruption of gas supply or flame failure
E135	Interruption of gas supply (internal error)
E135	Interruption of gas supply (internal error)
E154	Flow/ return sensor temperature test
E160	Fan or fan wiring fault
E270	Circulation fault (Dry fire)
E321	Hot water NTC fault
E384	False flame

BAXI ECOBLUE (COMBI & SYSTEM) Boiler Error/Fault Codes

Error Code	Possible Fault
E10	Outdoor Sensor Error
E20	Central Heating Thermistor Sensor Fault
E28	Flue Thermistor Fault
E54	HW Flow Sensor Fault
E78	Water Pressure Sensor Fault
E100	Internal Clock Time Error on PCB
E109	Poor Circulation
110	Overheat
111	Maximum Limit of Flow Temperature
117	Water pressure too high
118	Water pressure too low
119	System Pressure Low (<0.5 bar)
125	Water circulation fault
127	Legionella 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	Heating flow switch error (Ireland) Pressure Sensor Error (UK)
166	Air Pressure Switch Fault
270	Dry Fire
432	Earth connector error
433	Heat exchanger temperature exceeded (greater than 95 degrees)

BAXI ECOBLUE (HEAT) Boiler Error/Fault Codes

Error Code	Possible Fault
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; Sensor Fault, 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 or PSU Error
6 Red flashes	Miscellaneous error.

BAXI DUO-TEC /MEGAFLO Boiler Error/Fault Codes

Error Code	Possible Fault
E10	Outdoor sensor error
E20	Central Heating Thermistor Senor Fault
E28	Flue Thermistor Fault
E110	Boiler Overheat. Ensure radiators are bled of air
E119	Low water pressure. Add water to the system via the filling loop
E125	Primary Water Circulation Fault. Ensure radiators are bled of air
E131	Flue overheat lock out. This may follow a power cut, try reset
E133	Ignition 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/E161	Fan Fault
E164	Fan Fault
E167	PCB Fault

BAXI SOLO (HEAT) Boiler Error/Fault Codes

Error Code	Possible Fault
Flash Flash On	Fan Fault
Flash Off Flash	Incoming Voltage less than 180V
Flash Off On	Overheat lockout
Flash On Flash	PCB fault
Flash On On	PCB fault
Off Off Off	No power supply
On Flash Flash	No circulation/dry fire
On Flash On	Thermistor fault
On Off flash	Live and neutral reversed
On Off On	Ignition lockout
On Off Flash	PCB fault
On Off Flash	Low voltage wiring harness fault

BAXI GA RANGE Boiler Error/Fault Codes

Error Code	Possible 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 AVANTA RANGE Boiler Error/Fault Codes

Error Code	Possible Fault
E0	Temperature sensor fault
E1	Boiler overheat tripped
E2	Poor circulation
E3	PCB fault
E4	Ignition failure
E10	Poor/No circulation
E12	PCB Fault
E13	Heat exchanger thermal fuse tripped
E83/84/85/86/87	Fan fault normally E8

BAXI MAIN ECO COMPACT HEAT Boiler Error/Fault Codes

Error Code	Possible Fault
1 Green Flash	Boiler temp reached
3 Green Flashes	Boiler temp reached.Temporary error, self-reset, if continues will go to 3 red flashes
3 Green Flashes	Temporary Flame Loss. Temporary error, self-reset, if continues will go to 3 red flashes
4 Green Flashes	Communication error between PCB and Control. Temporary error, self-reset.
5 Green Flashes	Parameter Error On PSU/PCB. Temporary error, self-reset.
6 Green Flashes	Miscellaneous Error. Temporary error, self-reset.
1 Red Flash	Sensor Error; Sensor Fault, 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 or PSU Error
6 Red Flashes	Miscellaneous

If you’re facing challenges with your Baxi boiler or need professional advice, our team of fully qualified local plumbers in London is ready to assist you. We also offer emergency gas boiler repair services. Don’t just take our word for it—check out our customer reviews for peace of mind or contact us directly to talk about your requirements!