BoilerFaultCodesRemeha 1 9. Fault Code
Also written as 19 — same fault.
The Remeha 1 9. fault code means: your boiler has shut down because the water returning to the unit is too hot, meaning heat isn't being transferred properly to your radiators or taps.. It appears on 2 Remeha models in our database.
Technical description: Max.water temperature: Return temperature too high.
What causes the Remeha 1 9. fault?
This fault occurs when the water coming back into the boiler is nearly as hot as the water going out, suggesting the heat has nowhere to go. The most common reasons are a pump failure that isn't moving the water around your house, or a blockage such as closed radiator valves or a clogged heat exchanger. It can also be caused by a faulty sensor that is incorrectly reporting the water temperature to the control board.
This issue often surfaces during the first cold spell of autumn when heating systems are turned back on after a long summer break, which can cause internal pump components to seize.
DIY fix possible
Check that all radiator valves (TRVs) are fully openEnsure the pump is running if visibleCheck that the bypass valve is not closedReset the boiler once the system has cooled down
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Remeha models that show the 1 9. fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Remeha 1 9. 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