BoilerFaultCodesRemeha 2 5. Fault Code
Also written as 25 — same fault.
The Remeha 2 5. fault code means: your boiler is overheating because water isn't moving through the system quickly enough to carry the heat away.. It appears on 3 Remeha models in our database.
Technical description: Maximum water temperature: Rise in flow temperature too fast. Check: circulation pump; water flow through the unit; water pressure (0.8 bar min).
What causes the Remeha 2 5. fault?
This fault occurs when the water temperature inside your boiler rises too quickly, causing the system to shut down for safety. The most common reasons are a pump that has failed to circulate water, a blockage in the pipework, or low water pressure, all of which prevent heat from being moved away from the burner. In some cases, air trapped in the system can also block the flow and trigger this overheat warning.
This fault is more common in autumn when heating systems are switched back on after being idle all summer, which can cause internal pump parts to seize.
DIY fix possible
Check that your system water pressure is at least 1.0 bar on the pressure gauge.Ensure all radiator valves and internal stopcocks are fully open to allow water flow.Bleed all radiators to remove trapped air that might be blocking the circulation.
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Gas Safe Register →Remeha models that show the 2 5. fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha 2 5. 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 27 April 2026