BoilerFaultCodesMalvern 0.5 Fault Code
Also written as 05 — same fault.
The Malvern 0.5 fault code means: your boiler's internal water pressure is outside the required range, meaning it needs a simple top-up to function correctly.. It appears on 1 Malvern model in our database.
Technical description: Bar Vessel Pressure (Vessel Volume 4, 4, 8, 8, 12)
DIY fix possible
Locate the external filling loop hose connected to your boiler pipesOpen the valves slowly to allow water into the system until the gauge reads between 1 and 1.5 barClose both valves tightly and restart the boiler
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Malvern models that show the 0.5 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Malvern 0.5 fault code information on this page is sourced and cross-checked against the official Malvern service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026