Error Codes

If a Baxi boiler develops a problem, the boiler will display an error code to help you identify the issue. The most common of these error codes are explained below.

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Common Error Codes for Baxi Combi and system Boilers

Baxi 200 Combi 2
Baxi 400 Combi 2
Baxi 600 Combi 2
Baxi 800 Combi 2
Baxi Assure 500 Combi 2

Baxi 600 System 2
Baxi 800 System 2
Baxi Assure 500 System 2

Error code	Possible fault
A.00.28	Solar temperature sensor is either removed or measures a temperature below range.
A.00.29	Solar temperature sensor is either shorted or measures a temperature above range.
A.00.34	Outdoor temperature sensor expected but not detected.
A.02.06	Low system pressure in heating circuit.
A.02.18	OBD error.
A.02.36	Functional device disconnected.
A.02.37	Passive functional device disconnected.
A.02.45	Connection error.
A.02.46	Device priority error.
A.02.48	Unit function configuration error.
A.02.49	Failed node initialisation.
A.02.54	OpenTherm bus power supply error.
A.02.55	Incorrect or missing serial number.
A.02.76	Internal memory reserved for full customisation of settings. No further changes can be made.
E.00.04	Return temperature sensor disconnected.
E.00.05	Return temperature sensor short circuited.
E.00.16	DHW tank temperature sensor not connected.
E.00.17	DHW tank temperature sensor short-circuited.
E.00.20	The flue gas temperature sensor is not connected or measured a temperature below the range.
E.00.21	The flue gas temperature sensor has short-circuited or measured a temperature above the range.
E.01.04	Flame loss detected five times in 24 hours.
E.01.12	Temperature measured by return sensor greater than flow temperature.
E.01.17	No water circulation (permanent).
E.01.20	Maximum flue gas temperature reached.
E.02.13	Total stoppage of the boiler (antifreeze function not active).
E.02.17	Permanent communication failure between gas valve and boiler PCB.
E.02.35	Critical safety device disconnected.
E.02.39	Minimum pressure not reached after 6 minutes of automatic filling.
E.02.47	Connection to external device unsuccessful.
E.04.01	Flow temperature sensor short circuited.
E.04.02	Flow temperature sensor disconnected.
E.04.03	Maximum flow temperature exceeded or flow temperature sensor short circuited.
E.04.08	Maximum safe temperature value reached.
E.04.10	Burner failed to ignite after 4 attempts.
E.04.12	Ignition failure -flame monitoring.
E.04.13	Fan impeller blocked or maximum rpm exceeded.
E.04.17	Fault in gas valve control circuit.
E.04.18	The flow temperature is below the minimum temperature or the flow temperature sensor is not connected.
E.04.23	Communication internal stoppage.
E.04.254	Fault in gas valve control circuit.
E.04.29	Communication internal stoppage.
E.04.54	Fault in gas valve control circuit.
H.00.42	Pressure sensor open/faulty.
H.00.81	Room unit disconnected.
H.01.00	Temporary communication failure between gas valve and boiler PCB.
H.01.05	Maximum temperature difference value between flow and return reached.
H.01.08	Flow temperature increase in heating mode too quick. Temporary stoppage of 10 minutes.
H.01.14	Maximum flow or return temperature value reached.
H.01.18	No water circulation (temporary).
H.01.21	Flow temperature increase during domestic hot water operation too fast.
H.02.00	Reset in progress.
H.02.02	Waiting for configuration settings to be entered (CN1,CN2).
H.02.03	Configuration settings (CN1,CN2) not entered correctly.
H.02.04	PCB settings cannot be read.
H.02.05	Setting memory not compatible with the boiler PCB type.
H.02.07	Low pressure in heating circuit (permanently).
H.02.09	Partial stoppage of the boiler (antifreeze function active).
H.02.10	Total stoppage of the boiler (antifreeze function not active).
H.02.70	External unit heat recovery test failed.
H.03.00	No identification data for boiler safety device.
H.03.02	Temporary flame loss.
H.03.05	Power supply voltage too low.
H.03.54	Temporary flame loss. Shutdown due to the power supply voltage being too low.
I can't find my error code	Call Technical Support

Baxi Platinum Compact Combi
Baxi Duo-tec Compact Combi
Baxi Megaflo Compact System
Main Eco Compact Combi & System
Baxi 600 Combi & System
Baxi 800 Combi & System
Baxi Duo-tec Combi

Baxi Assure Combi & System
Baxi Platinum Combi
Potterton Assure Combi & System
Baxi Platinum + Combi
Baxi Megaflo System
Baxi EcoBlue Combi & System

Error code	Possible fault
E09	Gas valve connection fault.
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 sensor fault - short circuit/open circuit.
E28	Flue NTC sensor fault- short circuit/open circuit.
E40	Return central heating NTC sensor fault- short circuit/open circuit.
E50	DHW NTC sensor fault (tank boiler) - short circuit/open circuit.
E83 / E84 / E85 / E86 / E87	No communication.
E103	Safety Assist battery is exhausted.
E104	Faulty Safety Assist PCB.
E107	PCBs not synchronised.
E109	Precirculation alarm.
E110	(i) Boiler max. temperature exceeded for gradient (probable pump jammed or air in the circuit). (ii) Safety thermostat sensor tripped.
E118	Water pressure LOW (<0.5 bar).
E125	Water circulation fault.
E128	Safety error for frequent loss of flame.
E129	Safety error for frequent loss of flame with max correction during ignition during Calibration Function.
E130	Flue thermostat sensor tripped (lockout).
E133	Gas supply fault. Check the power supply, sensing electrode, spark electrode and cable.
E134	Elapsed time gas valve open without gas (short request in a short period).
E135	Internal error.
E154	Plausibility test (flow/return).
E160	Fan fault.
E270	Dry fire.
E317 / 162	Wrong power supply electrical frequency (Hz).
E321 / 163	Domestic Hot Water NTC sensor fault (s.c.).
E321 / 163	Domestic Hot Water NTC sensor fault (o.c.).
E384 / 164	False flame (parasitic flame).
E385 / 165	Under voltage.
E430 / 166	Water pressure temporary fault.
E430 / 166 + Flame 'crossed'	Water pressure test failed.
I can't find my error code	Call Technical Support

Error Codes

Common Error Codes for Baxi Combi and system Boilers

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