Baxi · 800 Combi 2
E.04.21 boiler fault code
800 Combi 2 current generation
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Renting? Report it to your landlord or housing provider first. They are responsible for gas safety and boiler repairs, and the repair should not cost you.
What E.04.21 means
E.04.21 indicates A difference was detected between the temperature sensors for burners 1 and 2.
Safe check
Record the displayed code. Do not open the casing or carry out internal checks; arrange a Gas Safe registered engineer.
When to contact an engineer
Arrange a Gas Safe registered engineer to investigate this boiler fault.
Safety notice
A boiler fault code alone is not a gas or carbon-monoxide emergency. If you smell gas, a CO alarm sounds, anyone feels unwell, or there is an unsafe flame, leave and call 0800 111 999 from outside.
Source and provenance
- Baxi 800 Combi 2 Installation and Service Manual · §11.2, Table 34, printed p. 77
installation and service manual
7745721