A00.34 Low

Remeha A00.34 Fault Code

Also written as A0034 — same fault.

The Remeha A00.34 fault code means: your boiler has lost the connection to the external sensor that tells it how cold it is outside, so it is currently operating in a default mode.. It appears on 1 Remeha model in our database.

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.

Technical description: TOutside Missing: Outside temperature sensor was expected but not detected
Typical repair cost £120-200 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Remeha models that show the A00.34 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Remeha A00.34 fault code information on this page is sourced and cross-checked against the official Remeha service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026