BoilerFaultCodesHeatline P.05 Fault Code
Also written as P05 — same fault.
The Heatline P.05 fault code means: your boiler is currently refilling its internal water system, which is a normal process that happens automatically after the system has been drained or topped up.. It appears on 7 Heatline models in our database.
Technical description: Filling the appliance
DIY fix possible
Wait 5-10 minutes for the boiler to complete the automatic filling sequence.Check that your external filling loop valves are fully closed if you recently topped up the system.If the code persists for more than an hour, switch the boiler off at the fused spur and back on again to reset.
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Heatline models that show the P.05 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Heatline P.05 fault code information on this page is sourced and cross-checked against the official Heatline service / installation manuals for each affected model.
- Heatline CaprizPlus 28 manual (PDF)
- Heatline CaprizPlus 24a manual (PDF)
- Heatline Compact 24 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026