BoilerFaultCodesWarmflow E48 Fault Code
The Warmflow E48 fault code means: your boiler has detected too much water pressure in the system, which can cause the safety valve to leak if left unaddressed.. It appears on 3 Warmflow models in our database.
Technical description: High System Pressure — filling loop left connected/open; insufficient expansion capacity; consult Service Engineer
DIY fix possible
Check that the silver braided filling loop valves are tightly closed.Locate a radiator and use a bleed key to release water into a cloth until the pressure gauge drops to 1.5 bar.Reset the boiler to clear the fault code.
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Warmflow models that show the E48 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Warmflow E48 fault code information on this page is sourced and cross-checked against the official Warmflow service / installation manuals for each affected model.
- Warmflow Agentis Boilerhouse manual (PDF)
- Warmflow Agentis External manual (PDF)
- Warmflow Agentis Internal manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026