BoilerFaultCodesRemeha ÿ9 Fault Code
Also written as 9 — same fault.
The Remeha ÿ9 fault code means: your boiler has shut itself down because it cannot move water around the system fast enough, causing it to overheat rapidly.. It appears on 1 Remeha model in our database.
Technical description: Lock-out; maximum temperature rise exceeded, dT between supply and return ≥ 22°C, rate of rise > 2,7°C/sec, no through flow, insufficient water, or shut down input activated
DIY fix possible
Check that all your radiators have their thermostatic valves fully openEnsure your system pressure is set correctly, typically between 1.0 and 1.5 bar on the gaugeCheck that the external pump isolation valves have not been accidentally closed
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Remeha models that show the ÿ9 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha ÿ9 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