P.05 Low

Glow-worm P.05 Fault Code

Also written as P05 — same fault.

The Glow-worm P.05 fault code means: your boiler is currently performing an automatic air-removal process after detecting a change in water pressure, and it will return to normal operation once this cycle finishes.. It appears on 10 Glow-worm models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Filling the product: The diverter valve is moved to the mid-position. The burner and pump are switched off (to fill or drain the product). If the pressure is lower than 0.05 MPa (0.5 bar) and then is above 0.07 MPa (0.7 bar) for longer than 15 seconds, the automatic purging function is activated. The function is activated for 15 minutes.

DIY fix possible

Wait for 15 minutes to allow the automatic purging cycle to completeCheck your boiler's pressure gauge to ensure it is between 1.0 and 1.5 barIf the pressure is below 1.0 bar, use the filling loop to top it up to the correct level

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Glow-worm models that show the P.05 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Glow-worm P.05 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