d.58 Low

Glow-worm d.58 Fault Code

Also written as D58 — same fault.

The Glow-worm d.58 fault code means: your boiler is currently identifying that the solar heating system is active and is not reporting a fault, but rather confirming it is communicating with your solar thermal setup.. It appears on 5 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: Solar circuit reheating function

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Glow-worm models that show the d.58 fault code

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

Source

Glow-worm d.58 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