Baxi Boiler fault & error codes

Boilers are pretty complicated pieces of kit, meaning there’s a long list of potential problems they can encounter if things stop working as they should. 

If you notice that your Baxi boiler isn’t providing your home with hot water or that your central heating isn’t functioning correctly, you’ll likely see an error code displayed on the system’s interface. These codes help engineers determine the problem with the boiler, especially if the issue isn't evident from other telltale signs right away.

To make the process easier, in this blog, we'll cover all of the most common error codes so that you can ensure any problems are resolved as quickly as possible.

Baxi boiler fault & error codes by boiler model

• Baxi Platinum+ 40kW error codes
• Baxi 600 combi  / Baxi 800 combi error codes
• Baxi 600 Heat error codes
• Baxi 200 Combi or Baxi 400 Combi error codes
• Baxi Duo-Tec or Baxi Megaflo error codes

Baxi Platinum+ 40kW error codes 

If performance and reliability are at the top of your list of priorities when looking for a new or replacement boiler, the Baxi Platinum+ will struggle to disappoint. Thanks to its high power rating, this combi boiler is an ideal option for larger homes with around 20 radiators and families with greater hot water demands. 

Baxi’s Platinum+ is a firm favourite among boiler engineers, too, as its front access panel means any repairs or adjustments can be carried out easily.

Error code	Problem
E20	Central heating negative temperature coefficient (NTC) fault.
E28	A fault with either the flue NTC, air pressure switch, or wiring or a blocked flue or condensate pipe.
E50	Hot water NTC fault.
E110	The safety thermostat was triggered due to internal overheating. The pump may need unblocking or replacing. Contact a Gas Safe engineer.
E119	Low water pressure.
E125	Circulation fault (primary circuit).
E130	Flue NTC tripped. An internal fault with the flue or the external flue pipe could be blocked.
E133	Interruption of the gas supply or flame failure.
E160	Fan or fan wiring fault.
E193	Pre-circulation fault.

Baxi 600 combi  / Baxi 800 combi error codes

Two similar models with matching error codes, the Baxi 600 and 800 are both great heating solutions. The Baxi 600 is all about performance and delivery in small spaces, making it a great choice for small and medium-sized homes with 2-3 bedrooms.

The Baxi 800 is a slight step up from that, boasting increased capacity and performance, making it a more suitable option for larger homes with greater hot water requirements.

Error code	Problem
E09	An issue with the gas valve connection cable.
E15	Gas valve command fault
E20	Central heating NTC fault
E28	Flue NTC fault.
E40	Central heating return NTC fault.
E83	No communication.
E109	Pre-circulation fault.
E110	One of the following issues may be present: The boiler’s max temperature exceeded for gradient (probable pump jammed or air in the circuit) The boiler’s max temperature exceeded (probable pump jammed or air in the circuit) The safety thermostat sensor has been triggered.
E118	The primary system water pressure is 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 wiring fault.
E270	Circulation fault.
E321	Hot water NTC fault
E384	False flame.

Baxi 600 Heat error codes

The Baxi 600 Heat is a standard boiler that can fit in a typical kitchen cupboard. There are various outputs available for this model, from 13kw to 30kw.

This is a boiler that embodies the phrase “small but mighty”, making it a good choice for homeowners looking for a powerful boiler that doesn’t take up too much space in their home.

The error codes display a little differently on the Baxi 600 Heat boiler than on other Baxi models listed in this guide, as you can see below.

2 flashes green	The BL terminals on the User Interaction and Controller are open circuit.
3 flashes green	No flame was detected during operation.
4 flashes green	Bad connection, a wiring fault or an internal communication fault.
5 flashes green	Parameter error or a faulty PU. Configuration error or a PCB fault.
6 flashes green	Possible internal fault in the combustion control unit.
1 flash red	Bad connection to flow or the return temperature sensor.
2 flashes red	One of the following issues may be present: Over-temperature thermostat on the heat exchanger activated No water flowing through the heat exchanger PCB over-temperature condition Flue fault resulting in recirculation or activation of the air pressure switch (if fitted).
3 flashes red	No ignition, no flame detected following ignition or a false flame signal detected.
4 flashes red	Fan calibration error or fan failure.
5 flashes red	Bad connection to PU, parameter error or a faulty PU.
6 flashes red	Bad connection, wiring fault or parameter error.

Baxi 200 Combi or Baxi 400 Combi error codes

In a similar dynamic to the ones we’ve mentioned before, the Baxi 200 and 400 are sibling boilers with slightly different qualities. 

The Baxi 200 Combi is a compact unit with an output as high as 24kw in the newest edition. The 400 is more suited to larger homes, with a maximum output of 30kw. 

The error codes are the same on these boilers to save confusion.

Error code	Problem
H.01 - .00	Temporary loss of communication between gas valve and boiler board. Fault in the air/gas unit.
H.01 - .05	The maximum difference between the flow and return temperature exceeded. Non-existent or insufficient circulation. Sensor error.
H.01 - .08	The flow temperature is increasing too fast in heating mode. Non-existent or insufficient circulation.
H.01 - .14	Maximum flow temperature value exceeded. Non-existent or insufficient circulation. Non-existent or insufficient circulation.
H.01 - .18	No circulation of water. Non-existent or insufficient circulation. Sensor error.
H.01 - .21	The flow temperature is increasing too fast in DHW mode. Non-existent or insufficient circulation. Sensor error.
H.02 - .02	No input of parameters C1/C2. PCB not configured.
H.02 - .03	Incorrect configuration settings C1/C2.
H.02 - .04	Parameter error. Incorrect parameters.
H.02 - .06	System water pressure. Water leak in the boiler. Water leak in the system.
H.03 -.00	Communication error with NTC flue sensor. Sensor not, or badly connected. Bad connection. Sensor fault.
H.03 -.01	Communication error with the HMI PCB. HMI is not connected.
H.03 -.02	No flame during operation. No ionisation current.
E.00 - .04	Return temperature sensor open-circuit. Sensor not or badly connected. Bad connection. Sensor fault.
E.00 - .05	Return temperature sensor open-circuit. Sensor not or badly connected. Bad connection. Sensor fault.
E.01 - .04	Loss of flame has been detected 5 times in 24 hours (with the burner on). No ionisation current.
E.01 - .11	Incorrect fan speed. External draught over the boiler. Defective gas/air unit.
E.01 - .12	Reset required. The temperature measured by the return sensor is greater than the flow temperature.
E.01 - .17	No circulation. Sensor not or badly connected. Sensor fault.
E.01 - .20	Maximum flue gas temperature value reached (>140ºC). No circulation. Sensor fault.
E.02 - .00	A boiler reset is in progress after the reset button was pressed.
E.02 - .07	No or low system water pressure. Low system pressure (less than 0.5 bar) boiler will not function.
E.02 - .16	On board CSU time-out. Check PCB for damage.
E.02 - .17	Permanent loss of communication between gas valve and boiler PCB. Fault in air/gas unit. Loose connection to the gas valve.
E.02 - .19	Jumper 1 changed. Check the position of jumper 1.
E.02 - .20	Jumper 2 changed. Check the position of jumper 2.
E.02 - .21	Jumper 3 changed. Check the position of jumper 3.
E.02 - .47	Connection to external device unsuccessful. Check wiring to the external device.
E.02 - .48	Configuration to external device unsuccessful. Check pairing to external.
E.04 - .00	Gas valve fault. Gas valve not detected.
E.04 - .01	Flow temperature sensor short-circuited. Sensor not or badly connected. Bad connection or a sensor fault.
E.04 - .02	Flow temperature sensor open-circuited. Sensor not or badly connected. Bad connection or sensor fault.
E.04 - .03	Critical flow temperature reached. Non-existent or insufficient circulation.
E.04 - .04	The flue temperature sensor has short-circuited. Sensor not or badly connected. Bad connection or sensor fault.
E.04 - .05	The flue temperature sensor is open-circuited. Sensor not or badly connected or a sensor fault.
E.04 - .06	Critical flue gas temperature value reached. No circulation. Sensor fault.
E.04 - .08	Maximum safe temperature value reached. No circulation. Sensor not or badly connected. Bad connection or sensor fault.
E.04 - .10	Failure to light (could be a gas supply issue).
E.04 - .12	False flame signal.
E.04 - .13	The fan rotor is blocked. Fan seized or wiring to fan damaged.
E.04 - .17	Problem with gas valve. Possible defective gas/air unit.

Baxi Duo-Tec or Baxi Megaflo error codes

The Baxi Duo-Tec is able to fit in a space as small as 290mm deep and can connect with the Baxi uSense smart thermostat system to help keep your home’s energy usage (and bills) to a minimum.

The Megaflo is a cylinder-based system made with larger homes and high hot water demands in mind. If you’ve got multiple bathrooms and need hot water from several different outlets simultaneously, the Megaflo could be the perfect solution for you.

Error code	Problem
E09	An issue with the gas valve connection cable.
E15	Gas valve command fault
E20	Central heating NTC fault
E28	Flue NTC fault.
E40	Central heating return NTC fault.
E83	No communication.
E109	Pre-circulation fault.
E110	Safety thermostat operated.
E118	The primary system water pressure is too low (< 0.5 bar).
E125	Circulation fault (primary).
E128	Frequent flame failure (12 times).
E130	Flue thermostat sensor tripped (lockout).
E133	Failure to light (could be a gas supply issue).
E135	Interruption of gas supply (internal error).
E154	Flow/return sensor temperature test.
E160	Fan or wiring fault.
E270	Circulation fault.
E321	Hot water NTC fault
E384	False flame.

Protect your home’s central heating with BOXT

Luckily, the majority of Baxi boiler problems are relatively quick and easy for qualified engineers to fix, provided they’re identified promptly. 

If you suspect that any of the issues mentioned above are to blame for your boiler’s malfunctioning, and the recommended fix isn’t as simple as pressing the reset button, always contact a Gas Safe registered engineer who’ll be able to come and assist you.

With appliances like boilers, it helps to always be prepared. Check out our boiler repair service - simply answer a few questions about your boiler, and one of our Gas Safe registered engineers will visit to diagnose and fix the problem.