BoilerFaultCodesGlow-worm P.08 Fault Code
Also written as P08 — same fault.
The Glow-worm P.08 fault code means: your boiler is currently in a manual mode used for filling the system with water or draining it, rather than operating in normal heating mode.. It appears on 1 Glow-worm model in our database.
Technical description: Filling or draining the product
DIY fix possible
Check that the boiler mode selector is not stuck in a commissioning or maintenance positionTurn the boiler off at the fused spur for 30 seconds to perform a hard resetEnsure your system pressure is at the correct level (usually between 1.0 and 1.5 bar) and the filling loop is fully closed
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Glow-worm models that show the P.08 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Glow-worm P.08 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026