Low
A.00.34 on Baxi 400 Combi 2

Your boiler is looking for an outdoor weather sensor that it cannot find or that has stopped communicating with the system.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Outdoor temperature sensor expected but not detected

From this model's manual
Verified against the Baxi 400 Combi 2 installation & service manual, page 73.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check if an outdoor sensor was recently installed or removedInspect the sensor wiring outside for any obvious damage or loose connectionsTurn the boiler power off and back on to see if the error clears

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