Question 1

What does error code E01 u Baxi & De Dietrich mean and how to fix it?

Accepted Answer

Burner ignition failure / flame loss (ignition lockout). Troubleshooting & fix: Closed gas valve, dirty ignition or ionization electrode, reversed live/neutral polarity in the wall socket, or faulty gas valve; after checking, hold the Reset (R) button for 2 seconds.

Question 2

What does error code E10 / E118 u Baxi & De Dietrich mean and how to fix it?

Accepted Answer

Heating water pressure too low in the system (below 0.5 bar). Troubleshooting & fix: Open the filling tap underneath the Baxi boiler and top up water pressure to 1.2 – 1.5 bar; if pressure drops frequently, repressurize the expansion vessel or replace the hydraulic pressure switch.

Question 3

What does error code E25 / E26 u Baxi & De Dietrich mean and how to fix it?

Accepted Answer

Maximum temperature rise rate exceeded / blocked circulation pump. Troubleshooting & fix: Insufficient heating water circulation through the exchanger – bleed the boiler, clean the return strainer mesh, and free the circulation pump rotor shaft if seized.

Question 4

What does error code E110 u Baxi & De Dietrich mean and how to fix it?

Accepted Answer

Safety high-limit overheating thermostat (STB) or flue gas thermostat tripped. Troubleshooting & fix: The boiler overheated above 100 °C due to closed radiator valves, an airlocked heat exchanger, or a faulty heating water NTC temperature sensor; let the boiler cool down and press Reset.

Question 5

What does error code E133 / E128 u Baxi & De Dietrich mean and how to fix it?

Accepted Answer

Gas supply interruption / flame loss on Baxi Duo-tec & De Dietrich condensing boilers. Troubleshooting & fix: Clogged condensate drain trap (water flooded the combustion chamber!), frozen flue terminal in winter, worn ionization electrode, or gas valve calibration required.

Baxi & De Dietrich Error Codes: E01, E10, E25/E26, E110, E133 – Error Code Meaning, Troubleshooting & Repair

Error Code Reference Table for Baxi & De Dietrich and step-by-step repair procedure:

Error Code	Meaning / Fault Symptom	Most Common Cause & Repair Procedure
E01	Burner ignition failure / flame loss (ignition lockout)	Closed gas valve, dirty ignition or ionization electrode, reversed live/neutral polarity in the wall socket, or faulty gas valve; after checking, hold the Reset (R) button for 2 seconds.
E10 / E118	Heating water pressure too low in the system (below 0.5 bar)	Open the filling tap underneath the Baxi boiler and top up water pressure to 1.2 – 1.5 bar; if pressure drops frequently, repressurize the expansion vessel or replace the hydraulic pressure switch.
E25 / E26	Maximum temperature rise rate exceeded / blocked circulation pump	Insufficient heating water circulation through the exchanger – bleed the boiler, clean the return strainer mesh, and free the circulation pump rotor shaft if seized.
E110	Safety high-limit overheating thermostat (STB) or flue gas thermostat tripped	The boiler overheated above 100 °C due to closed radiator valves, an airlocked heat exchanger, or a faulty heating water NTC temperature sensor; let the boiler cool down and press Reset.
E133 / E128	Gas supply interruption / flame loss on Baxi Duo-tec & De Dietrich condensing boilers	Clogged condensate drain trap (water flooded the combustion chamber!), frozen flue terminal in winter, worn ionization electrode, or gas valve calibration required.