Baxi Boiler Fault Codes
Baxi Boiler Fault Codes
Baxi has been manufacturing since 1866 and is considered a respected heating brand in the UK. Croston plumbing and heating install many boiler brands, including Baxi & Worcester Bosch.
As a brand, Baxi usually is quite a reliable brand of boiler, but even the most reliable boilers sometimes encounter issues or problems.
When your Baxi boiler displays an error code, it will lock out to prevent any further damage to the boiler or potential more hazardous problems to those in your home.
Other Issues that Can Effect Your Boiler
You may encounter your boiler not operating and not displaying a fault code. In this case, it’s worth checking your water, gas, and electricity supplies to ensure there is no issue with supply. If you have a prepay meter, make sure you have credit available. Also, check your property has running water from the cold taps, that your gas is working by lighting the hob or gas fire and that your electricity is working by turning on a light within your home.
Your boiler may be on a separate electrical circuit if the rest of your home has electricity, but the boiler LCD isn’t displaying anything. So then, it can be that your boiler may not receive power, and you may need to call an electrician or Gas Safe engineer.
Baxi Boiler Lockout
When your Baxi boiler locks out, an error code will be displayed on the boiler dashboard screen to help you identify the issue or problem. You can identify the fault code by checking your boiler manual, although many people find it easier to jump onto Google and type in the error code. At Croston Plumbing and Heating, we are your local Baxi fault code experts with a wealth of experience in repairing and maintaining Baxi boilers.
Nowadays, you can self-fix some fault codes, but some require a Gas Safe registered engineer to investigate. Therefore, this information is to help you identify your boiler issue. Caution: Never open your boiler’s casing and attempt to fix it yourself.
What are the common Baxi Boiler 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. Water leak on the boiler. Water leak 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. |
Error Code |
Possible Fault |
| E20 | Central heating NTC fault |
| E28 | Flue NTC fault, air pressure switch fault, blocked flue, blocked condensate, or wiring fault. |
| E50 | Hot water NTC fault |
| E110 | E110 safety thermostat operated |
| E119 | The water pressure switch was 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 |
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 frequent 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. |
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 |
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 |
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) |
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. |
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 |
| E168 | PCB lock out |
| E193 | Circulation fault |
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 |
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) |
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 |
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 |
Are you interested in replacing your boiler and avoiding recurrent Baxi Boiler Fault Codes and problems?
Croston Plumbing & Heating specialists are here to assist. If there is a problem, one of our highly skilled repair technicians will be on hand to figure it out quickly and efficiently.
Whether or not you need a new boiler, our experts can help you with this decision. Get in touch with us today by calling 01257452879 or browse our site for additional information.
Here are some of the signs that you boiler needs replacing:
Noise
A sure sign that your boiler is due to be replaced is the kettling, gurgling and banging sounds that you might be hearing from your boiler when you run the hot water tap or turn on the central heating
Strange smells
While carbon monoxide does tend to be odourless, some gas companies do add a scent to help it become easier for you to detect if a leak has occurred. An eggy, sulphur-like smell around your boiler is a sure sign that there is a carbon monoxide leak and you should open all the windows and get out of the house as quickly as possible. Contact the Gas Emergency Services as soon as you can.
Yellow flame
A healthy boiler that’s working well should burn with a blue flame. However, if you’ve noticed a yellow flame on your boiler, this could be a sign of a serious issue such as a carbon monoxide problem. This gas is colourless and odourless and often, a yellow flame is the first sign that there’s a problem so it’s important to keep your eye out for it. If exposure levels are high enough, carbon monoxide can lead to serious illness or even be fatal.
Increase in energy bills
A boiler that is getting old and is increasingly less and less efficient can cost more money than most people can afford to spare. And, upgrading to a boiler that includes modern smart controls will not only improve efficiency but also give you a greater control over your energy usage and spending.
Frequent breakdown
Are you noticing that your boiler is break downing regularly or you are topping up your water pressure every week?
Reduced efficiency
When it comes to energy efficiency, some boilers are just missing the mark due to age. A boiler that’s rated ‘A’ in terms of efficiency will have an energy efficiency level of at least 90%. On the other hand, a boiler that’s rated ‘G’ will have an efficiency level of around 70%, meaning that for every £1 you spend on your energy bill, you’re losing 30p in wasted energy.
Expensive & difficult to find parts
If you’re having increasing problems with your boiler and you have been told by your boiler engineer that new parts are hard to find, it’s a clear sign that your boiler will probably need to be replaced soon. The older a boiler gets, the less likely it is that parts will be readily available. And if you’re struggling to find an engineer who is experienced with the type of boiler that you have, that’s even more reason to consider replacing it.
Do you Need Boiler Finance?
We offer a range of finance options to help cover the cost of your new boiler and installation. All our engineers are Gas Safe registered, and we prioritise all boiler breakdowns to help get you warm and comfortable again as quickly as possible.
What areas do we cover?
At Croston Plumbing and Heating, we are your local, new boiler installation experts covering all areas across the North West, including