Baxi Boiler Fault Codes

While we all want our boiler to run reliably, things can and do go wrong from time to time.  And in those moments, you should always remember that we are only a phone call away.

But to help us know what might be wrong with your boiler, it will be flashing a fault code on its screen.  That little bit of information can save us time to diagnose the problem and potentially even save money because we may be able to help you fix the issue over the phone.

As a Baxi approved boiler installed, we want to help you identify what fault codes you may be experiencing and what they mean.

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.01 – 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 – 06 – Permanent Fault – Flue temperature sensor open-circuited. Sensor not or badly connected. Bad connection. 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.