Baxi Boiler Fault Codes
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We know it's frustrating when your boiler displays an error code, which is why we've listed some common boiler error codes below. If you're still stuck, do give us a call on 01892 489771 or click here to email us and one of our team will be able to assist.

BAXI 200 COMBI / BAXI 400 COMBI
Error Codes | Possible Fault |
---|---|
H.01 – .00 | Temporary Fault – Temporary loss of communication between gas valve and boiler board. Fault in air/gas unit. Loose connection to 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. Water leak on boiler. Water leak on 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 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 – On board CSU time-out. Check PCB for damage. |
E.02 – .17 | Permanent Fault – Permanent loss of communication between gas valve and boiler PCB. Fault in air/gas unit. Loose connection to gas valve. |
E.02 – .19 | Permanent Fault – Jumper 1 changed. Check position of jumper 1. |
E.02 – .20 | Permanent Fault – Jumper 2 changed. Check position of jumper 2. |
E.02 – .21 | Permanent Fault – Jumper 3 changed. Check 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 present even though there is no flame. The burner remains very hot (CO2 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 gas valve. Defective gas/air unit. |
BAXI PLATINUM+ 40KW
Error Code | Possible Fault |
---|---|
E20 | Central heating NTC fault |
E28 | Flue NTC fault, air pressue switch fault, blocked flue, blocked condensate or wiring fault. |
E50 | Hot water NTC fault |
E110 | E110 safety thermostat operated |
E119 | Water pressure switch not operated |
E125 | Circulation fault (primary circuit) |
E130 | Flue NTC operated |
E133 | Interruption of gas supply or flame failure |
E160 | Fan or fan wiring Fault |
E193 | Pre-circulation fault |
BAXI 600 COMBI / BAXI 800 COMBI
Error Code | Possible Fault |
---|---|
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 NTC fault. |
E28 | Flue NTC fault. |
E40 | Central heating return NTC fault. |
E50 | DHW NTC 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 | i) 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. |
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 NTC sensor fault (s.c.) OR Domestic Hot Water NTC sensor fault (o.c.). |
E270 | Circulation fault (dry fire). |
E317 | Wrong power supply electrical frequency (Hz). |
E321 | Hot water NTC fault. |
E384 | False flame. |
E385 | Under voltage. |
E430 | Water pressure temporary test. |
E430 + Flame ‘crossed’ | Water pressure test failed. |
BAXI 600 HEAT / MAIN ECO COMPACT HEAT
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 airpressure 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
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 |
ECOBLUE (COMBI & SYSTEM)
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) |
ECOBLUE (HEAT)
Error Code | Possible Fault |
---|---|
1 Green flash | Boiler temp reached |
3 Green flashes | Temporary Flame Loss |
4 Green flashes | Communication error between PCB and Control |
5 Green flashes | Parameter Error On PSU/PCB |
6 Green flashes | Miscellaneous Error |
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 |
DUO-TEC /MEGAFLO
Error Code | Possible Fault |
---|---|
E10 | Outdoor sensor error |
E20 | Central Heating Thermistor Senor Fault |
E28 | Flue Thermistor Fault |
E110 | Boiler Overheat |
E119 | Low water pressure |
E125 | Primary Water Circulation Fault |
E131 | Flue overheat lock out |
E133 | Ignition fault |
E160/E161 | Fan Fault |
E164 | Fan Fault |
E167 | PCB Fault |
E168 | PCB lock out |
E193 | Circulation fault |
SOLO (HEAT)
Error Code | Possible Fault |
---|---|
Flash Flash On | Fan Fault |
Flash Off Flash | Incoming Voltage less then 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 |
GA RANGE
Error Code | Possible Fault |
---|---|
E4 | Ignition failure |
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) |
AVANTA RANGE
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 |
MAIN ECO COMPACT HEAT
Error Code | Possible Fault |
---|---|
1 Green Flash | Boiler temp reached |
3 Green Flashes | Boiler temp reached |
3 Green Flashes | Temporary Flame Loss |
4 Green Flashes | Communication error between PCB and Control |
5 Green Flashes | Parameter Error On PSU/PCB |
6 Green Flashes | Miscellaneous Error |
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 |