Don’t Panic! Deciphering Baxi Boiler Fault Codes Made Easy

Baxi is a popular choice for boilers, heat pumps, and other related products in Hemel Hempstead and surrounding areas. These appliances are an essential part of daily life, especially during the chilly winters of the UK. Therefore, when your boiler or heating system is acting up and flashing an indecipherable code, it is only natural to feel panicked. Not anymore. With this informational blog, we aim to crack all the Baxi boiler fault codes, splitting them out by model name, just for you!

We understand if you’d rather directly speak to our Gas Safe registered engineers who are Baxi boiler experts. Call 01442 832202 or email info@gastechheatingltd.co.uk now.

Baxi Platinum error codes

1. E20 – This error code refers to the “Central heating NTC error” message which suggests a problem with the central heating NTC (Negative Temperature Coefficient) sensor in your heating system. The NTC sensor is responsible for measuring temperature.
2. E28 – This is caused by “Error with the NTC (Negative Temperature Coefficient) flue, air pressure switch or blocked flue or condensate”, which can be triggered by problems with temperature sensors, air pressure switches, or obstructions in the flue or condensate drain.
3. E50 – The possible cause could be a “Hot water NTC (Negative Temperature Coefficient) error”. This indicates a problem with the NTC sensor responsible for measuring the temperature of the hot water in your heating or hot water system. Regular boiler servicing will help deter issues like this.
4. E110 – This error code is triggered by “Thermostat operated safety” which typically refers to a safety feature in a heating or HVAC system that is controlled by a thermostat. The safety feature is designed to ensure the system operates within safe temperature ranges and prevents overheating or other potential hazards.
5. E119 – This error corresponds to the message “Water pressure switch error – not operated”. It means there’s an issue with the water pressure switch in your heating or hot water system. The water pressure switch is responsible for detecting and regulating water pressure within the system.
6. E125 – This Baxi fault code means there’s an issue with the circulation of fluid or heat in the primary circuit of your heating system. This can affect the overall performance and efficiency of the system.
7. E130 – This is the “Flue NTC (Negative Temperature Coefficient) operation error” in your Baxi boiler. This refers to a problem with the NTC sensor in the flue of your heating or HVAC system. This sensor is designed to measure temperature in the flue or exhaust gases.
8. E133 – This refers to the “Gas supply error or flame failure” which indicates that your heating or combustion system has encountered an issue related to the gas supply, which can lead to a flame failure. This is a safety mechanism to prevent potentially hazardous situations.
9. E160 – This is a “Fan or fan wiring error” in your heating or HVAC system. The fan plays a crucial role in circulating air and maintaining system efficiency.
10. E193 – This error code means there is a “Pre-circulation error” in your Baxi boiler. The pre-circulation system is responsible for circulating fluids, such as water or coolant, before the main heating or cooling operation begins.

Baxi EcoBlue error codes

11. 110 – The error message equivalent to this code is “Overheated – try bleeding your radiators”. This means that your heating system may be overheating due to trapped air in the radiators.
12. 117, 118, and E78 – These error codes all correspond to water pressure issues. 117 and 118 refer to “Water pressure too high” and “Water pressure too low” respectively. And E78 refers to the “Water pressure sensor fault”. It is advisable to seek professional help to tackle these issues.
13. 125 and E109 – These error codes refer to circulation errors in your boiler. 125 means there’s a “Water circulation fault” and E109 refers to a “Poor circulation” in your heating system.
14. 128 and 133 – If your boiler is experiencing flame-related issues, you should get one of these codes. 128 refers to “Loss of flame during operation” and 133 means there’s the “Safety time to establish flame exceeded” fault in your boiler. It is advisable to have a boiler engineer take a look at your heating system at the soonest.
15. E10 – This Baxi fault code refers to the “Outdoor sensor error” which suggests a problem with the outdoor sensor in your heating or HVAC system. This sensor is typically responsible for measuring outdoor temperature or other environmental conditions.
16. E20 – This code is triggered by a “Central heating thermistor sensor fault” in your boiler. A thermistor is a type of temperature sensor.
17. E28 – This code refers to the “Flue thermistor fault” which suggests an issue with the thermistor sensor in the flue of your heating or HVAC system.
18. E54 – E54 or “Domestic hot water (DHW) flow sensor fault” indicates a problem with the flow sensor responsible for measuring the domestic hot water flow in your heating or hot water system.
19. E100 – This error code means “Internal clock time error on printed circuit board (PCB)”. The internal clock is used for timing and scheduling functions in the system.
20. 111 – This error may be caused by the “Maximum limit of flow temperature” issue in your Baxi boiler system. It’s a safety feature to prevent the system from producing excessively hot air or water, which could lead to system damage, energy inefficiency, or even safety hazards.
21. 119 – This error code is displayed when the system pressure is too low.
22. 127 – This fault code corresponds to the “Legionella (cause of Legionnaires’ disease) protection temperature not reached” issue. Legionella bacteria can proliferate in warm water systems, leading to the risk of Legionnaires’ disease.
23. 153 – 153 or “Forced reset unit unlocked” error suggests that a forced reset of your heating or HVAC unit has been performed, and the unit is now unlocked. A forced reset is typically a procedure to clear error codes or issues and restore normal operation.
24. 160 – This indicates there’s some fault in the fan. Calling in an engineer to repair the system is advisable.
25. 162 and 166 – Both these codes refer to an error with your boiler’s air pressure switch. Regular maintenance and servicing are useful measures to prevent these issues. At Gas Tech Heating, we offer 24/7 services, so feel free to call us for any repair work related to your Baxi boiler.
26. 164 – This code means two different things based upon your geographic location e. “Pressure Sensor Error (UK) – Heating flow switch error (Ireland)”.
27. 270 – This code means there’s a “Dry fire” issue in your boiler system. This typically refers to a situation where a heating or combustion system operates without the presence of fuel or water, which is essential for its proper operation. Dry firing can be a potentially damaging condition for the system and should be avoided.
28. 432 – 432 or “Earth connector error” suggests that there’s a problem with the electrical grounding of your heating or HVAC system. Proper electrical grounding is essential for safety and system reliability. Call in a registered engineer at the soonest.
29. 433 – This error code refers to the error message “Heat exchanger temperature exceeded (greater than 95 degrees)”.

EcoBlue Advance / Ecoblue Regular Gas Boiler flashing light fault codes

30. Green flashes – 1 green flash means boiler temperature has been reached and it requires no action. 3 green flashes mean “Temporary flame loss. Boiler will self-reset, if fault continues you will see 3 red flashes”. 4 green flashes refer to the message “Communication error between printed circuit board (PCB) and control. Temporary error, will self-reset”. 5 flashes are an indication of “Parameter error on printed circuit board (PCB). Temporary error, will self-reset”. Finally, 6 green flashes mean it’s an “Miscellaneous error. Temporary error, will self-reset”.
31. Red flashes – 1 red flash refers to a “Sensor error, temperature fault or flow fault”. 2 flashes will mean that you have the “Boiler overheat tripped” situation in place. 3 red flashes indicate the “Ignition fault. Boiler has attempted to light 5 times and failed”. When there are 4 red flashes, there’s fault in the fan. 5 flashes indicate the “Parameter storage unit (PSU) error” and 6 flashes mean “Miscellaneous error” in your heating system.

Do not ignore the red flashes, call in a professional and trustworthy engineer right away. The green flashes may be an indication of the fact that your heating system can do with a servicing.

Baxi Duo-tec/Megaflo error codes

32. E10 – This code refers to the “Outdoor sensor fault”.
33. E20 – This Baxi error code means there’s a “Central heating thermistor sensor error” in your boiler model.
34. E28 – This code is triggered by the “Flue thermistor error”.
35. E110 – This code refers to the boiler overheat error.
36. E119 – You’ll most likely see this error code when there’s low water pressure error.
37. E125 and E193 – These errors correspond to circulation error in your boiler model. E125 specifically indicates an issue with the primary water circulation.
38. E131 – this code refers to the “Flue overheat lockout error”.
39. E133 – When there’s an ignition error in your boiler, you’ll most likely see this code.
40. E160 and E161 – Both these codes suggest a fault with your Baxi model’s fan.
41. E164 – This code indicates an issue with the pressure sensor fault.
42. E167 and E168 – E167 refers to a “Printed circuit board (PCB) error” and E168 refers to a “Printed circuit board (PCB) lockout error”. This suggests that the printed circuit board (PCB) in your heating or HVAC system has entered a lockout state due to a fault or safety concern. This lockout prevents the system from operating to avoid further issues.

Baxi 200 / 400 Combi Gas Boiler error codes

43. H.01 – .00 – This code refers to the cause “Loss of communication between gas valve and boiler board. Possible fault in air/gas unit or loose connection to gas valve”.
44. H.01 – .05 – the reason behind this code could be that the “Difference between the flow and return temperature is too high, sensor error or insufficient circulation”.
45. H.01 – .08 – This code suggests that the problem is with a “Sensor fault, flow temperature increasing too fast in heating mode or insufficient circulation”.
46. H.01 – .14 – The message corresponding to this code is “Maximum flow temperature value exceeded or insufficient circulation – temporary fault”.
47. H.01 – .18 – This issue is caused by “No water circulation, insufficient circulation or sensor error”.
48. H.01 – .21 – This Baxi fault code refers to a “Temporary error – flow temperature increasing too fast in domestic hot water (DHW) mode, insufficient circulation or sensor error”.
49. H.02 – .02 – The possible cause could be “Temporary error – no input of parameters C1/C2. Printed circuit board (PCB) not configured”.
50. H.02 – .03 – The reason behind this error code could be a “Temporary error- incorrect configuration settings C1/C2″.
51. H.02 – .04 – This can also be a “Temporary error- parameter fault. Incorrect parameters”.
52. H.02 – .06 – This could be a temporary error caused by system water pressure, water leak on the boiler, or water leak on the system.
53. H.03 -.00 – The possible cause is “Temporary error with communication, negative temperature coefficient thermostat (NTC) or flue sensor. Sensor could also be unconnected or have a bad connection”.
54. H.03 – .01 – There could be a communication error with the printed circuit board (PCB).
55. H.03 – .02 – This may be caused by a “Flame error – no flame during operation”.
56. E.00 – .04 – The possible cause of this error is “Return temperature sensor open-circuit. Sensor not or badly connected”.
57. E.00 – .05 – This may be caused by the return temperature sensor short-circuit. Sensor may be not connected or badly connected.
58. E.01 – .02 – The possible cause is “Temperature measured by return sensor greater than flow sensor”.
59. E.01 – .04 – This may arise because of “Loss of flame detected 5 times in 24 hours (with burner on)”.
60. E.01 – .11 – This code may be triggered due to “Incorrect fan speed – external draught over the boiler or defective gas/air unit”.
61. E.01 – .12 – This can be an indication of the fact that your boiler “Requires reset – temperature measured by return sensor greater than flow temperature”.
62. E.01 – .17 – Reset the boiler. There’s no circulation. Sensor fault, either not connected or has a bad connection.
63. E.01 – .20 – The code refers to the “Maximum flue gas temperature reached. No circulation or sensor fault”. issue.
64. E.02 – .00 – The reset button has been pressed.
65. E.02 – .07 – No or low system water pressure. system pressure less than 0.5 bar.
66. E.02 – .16 – Permanent fault, caused by channel service unit (CSU) time-out or printed circuit board (PCB) damage.
67. E.02 – .17 – Loss of communication between gas valve and boiler printed circuit board (PCB) or fault in air/gas unit.
68. E.02 – .19 – Jumper 1 changed – check position of jumper 1. Jumpers are small connectors that can be placed on pins or connectors on a circuit board to change or configure certain settings.
69. E.02 – .20 – Jumper 2 changed – check position of jumper 2.
70. E.02 – .21 – Jumper 3 changed – check position of jumper 3.
71. E.02 – .47 – This refers to the “Wiring to external device error”
72. E.02 – .48 – Configuration to external device unsuccessful – check pairing to external device.
73. E.04 – .00 – The problem could be with the gas valve.
74. E.04 – .01 – Flow temperature sensor short-circuited. Sensor not or badly connected, bad connection or sensor fault.
75. E.04 – .02 – Permanent fault. Flow temperature sensor open-circuited, sensor not or badly connected, bad connection or sensor fault.
76. E.04 – .03 – Permanent fault. Critical flow temperature reached, non-existent or insufficient circulation.
77. E.04 – .04 and E.04 – .05 – Permanent fault. Flue temperature sensor short-circuited, sensor not or badly connected, bad connection or sensor fault.
78. E.04 – .06 – Permanent fault. Critical flue gas temperature value reached, no circulation or sensor fault.
79. 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.
80. E.04 – .10 – Failure to light (this could be a gas supply issue).
81. 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.
82. E.04 – .13 – Permanent fault. Fan rotor blocked, fan seized or wiring to fan damaged.
83. E.04 – .17 – Permanent fault. Problem with gas valve or defective gas/air unit.

These error codes and corresponding messages are heavily technical terms that can be efficiently assessed and addressed by experienced boiler engineers. Do not panic when you encounter one of these. Contact us right away, and one of our experts will be your guide.

Baxi 600 Combi Gas Boiler error codes

84. E09 and E15 – Both these codes refer to gas valve problems in your Baxi boiler. E09 may be caused by the gas valve connection cable and E15 could arise due to a gas valve command fault.
85. E10 – this may be caused due to “External probe fault”.
86. E12 and E13 – The codes refer to the issues “Differential water flow switch fault (still open)” and “Differential water flow switch fault (still closed)” respectively.
87. E20 – The possible cause could be a “Central heating negative temperature coefficient (NTC) thermostat fault.
88. E28 – This may be caused by “Flue negative temperature coefficient (NTC) thermostat fault”.
89. E40 – This code refers to the “Central heating return negative temperature coefficient (NTC) thermostat fault”
90. E50 – The possible cause may be “Domestic hot water (DHW) negative temperature coefficient (NTC) thermostat sensor fault (tank boiler) (s.c.) or DHW NTC sensor fault (tank boiler) (o.c.)”.
91. E83/E84/E85/E86/E87 – When there’s no communication, one of these codes will be displayed.
92. E109 – Pre-circulation fault.
93. 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.
94. E118 – Primary system water pressure is too low (< 0.5 bar).
95. E125 and E270 – E125 refers to circulation fault (primary) and E270 refers to circulation fault (dry fire).
96. E128 – This refers to frequent flame failure (12 times).
97. E129 – Safety error for frequent loss of flame with max correction during the ignition during Calibration Function.
98. E130 – Flue thermostat sensor tripped (lockout).
99. E133 – Failure to light (could be a gas supply issue).
100. E134 – Elapsed time gas valve open without gas (short request in a short period).
101. E135 – Interruption of gas supply (internal error).
102. E154 – Flow/return sensor temperature test.
103. E160 – Fan or fan wiring fault.
104. E163 – Domestic hot water (DHW) negative temperature coefficient (NTC) thermostat sensor fault (s.c.) or DHW NTC sensor fault (o.c.).
105. E317 – Wrong power supply electrical frequency (Hz).
106. E321 – Hot water negative temperature coefficient (NTC) fault.
107. E384 – This could be a false flame error.
108. E385 – Under voltage.
109. E430 – Water pressure temporary test.
110. E430 + Flame ‘crossed’ – Water pressure test failed.

Baxi MainEco error codes

111. Green flashes – 1 green flash means “Boiler temperature reached – no action required”. 3 green flashes refer to the error “Temporary flame loss – this is a temporary error; the system should reset on its own”. 4 flashes refer to “Communication error between printed circuit board (PCB) and Control – this is a temporary error, the system should reset on its own”. Similarly, 5 flashes mean “Parameter error on parameter storage unit (PSU) or printed circuit board (PCB) – this is a temporary error, the system should reset on its own”. Finally, 6 flashes indicate miscellaneous error.
112. Red flashes – 1 red flash is given when there is a “Sensor error, sensor fault, temperature fault or flow fault – this is a temporary error, the system should reset on its own”. 2 flashes are shown for the “Boiler overheat tripped” error. 3 red flashes are triggered when there is “Ignition fault. Boiler has attempted to light 5 times and failed”. 4 and 5 flashes are shown for fan fault and parameter storage unit (PSU) error respectively. 6 flashes are for miscellaneous errors.

Baxi Avanta Range error codes

113. E0 – This code refers to the “Temperature sensor fault”.
114. E1 – This code corresponds to the error message “Overheated – try bleeding your radiators”.
115. E2 – This code is triggered due to “Poor circulation – try bleeding your radiators”.
116. E3 and E12 – Both these codes refer to printed circuit board (PCB) faults.
117. E4 – This may be caused by “Ignition failure – try bleeding your radiators”.
118. E10 – This Baxi code refers to poor or no circulation.
119. E13 – This refers to the message “Heat exchanger thermal fuse tripped”.
120. E83 / 84 / 85 / 86 / 87 – This corresponds to the message “Fan fault normally E8” which suggests that a fault or error related to the fan in your heating or HVAC system has occurred. The “E8” is likely an error code associated with the specific type of fan fault.

Baxi GA Range error codes

121. E53 – Poor combustion, flue terminal may be blocked.
122. E110 and E125 – System is overheated, try bleeding your radiators.
123. E117 – System water pressure is high, try bleeding water from your radiators.
124. E118 – System water pressure is low.
125. E133 – This could be due to a gas supply fault.
126. E4 – This may be caused by ignition failure.
127. E09 – This has likely occurred due to a gas valve wiring fault.
128. E10 – This code refers to “Outdoor sensor error”.
129. E15 – this code is triggered because of a “Gas valve connection fault”.
130. E20 – Central heating thermistor sensor fault.
131. E28 – Flue thermistor fault.
132. E40 – Central heating return thermistor fault.
133. E53 – Flue obstruction may cause this error.
134. E55 – this code may be triggered when calibration is required.
135. E78 – This code refers to the water pressure sensor fault.
136. E92 – Combustion test alarm during auto-setting.
137. E109 – The possible cause could be poor circulation.
138. E128 and E129 – Loss of flame during operation and Loss of flame during calibration respectively.
139. E135 – This may be an indication of an internal error.
140. E154 – Primary flow fault.
141. E160 – This may be caused by a fan fault.
142. E270 – The possible cause could be dry fire.
143. E317 – Wrong power supply (Hz).
144. E321 – Not water thermistor fault.
145. E384 – Flame detected when gas valve is off.
146. E385 – Low voltage (less than 195v).

Baxi Solo error codes

147. FLASH FLASH ON – This can be a fan error.
148. FLASH OFF FLASH – When the voltage is less than 180V.
149. FLASH OFF ON – It refers to overheat lockout.
150. FLASH ON FLASH, FLASH ON ON, and ON ON FLASH – These codes should be about a printed circuit board (PCB) error.
151. OFF OFF OFF – There’s no power.
152. ON FLASH FLASH – Circulation error or dry fire.
153. ON FLASH ON – Thermistor error.
154. ON OFF FLASH – Live and neutral reversed error.
155. ON OFF ON – This may refer to an ignition error.
156. ON ON ON – Low voltage wiring harness error.

Over to you

This article has helped you decode the fault codes in your boiler machine depending on the model of your Baxi boiler. This is the first step to understanding the issue at hand. And we do understand that it must be tempting to try out popular DIY methods such as resetting the boiler, thawing out the pipes, checking connections and wires, etc. However, you should always keep your safety and the system’s effectiveness in mind. That is to say, do not take things into your hands unless you’re a professional boiler engineer who has complete knowledge of the error codes and the system.

At Gas Tech Heating, we are a team of Gas Safe registered engineers, and we boast over 40 years of experience between us. We have the knowledge and expertise needed to understand your Baxi boiler’s error codes. And we can efficiently fix them. We also offer 24/7 boiler repair services, so no matter what the issue is, you can always rely on us. Contact us to discuss your Baxi boiler issues now.