What does the Glow-worm d.66 fault code mean?

Your boiler is simply indicating that the 'warm start' feature is currently active, which keeps a small amount of water pre-heated so you get hot water faster when you turn on the tap.

How much does it cost to fix Glow-worm error code d.66?

Cost varies. Contact a Gas Safe registered engineer for a quote.

Glow-worm d.66 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Activationofthewarmstartfunctionfordomestichotwater

Shared across the Ultimate 3 range

This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.

DIY fix possible

This is a status code, not a fault, so no repair is required.If you wish to turn this feature off, access your boiler's user menu.Navigate to the 'Warm Start' or 'Comfort' setting and toggle it to 'Off' if you prefer to save energy.

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All 159 fault codes on the Ultimate3 Combi

Seeing a different code? Every code this model can display, in one place.

Your boiler is simply indicating that the 'warm start' feature is currently active, which keeps a small amount of water pre-heated so you get hot water faster when you turn on the tap.

What the manual says

DIY fix possible

Avoid the next call-out bill

All 159 fault codes on the Ultimate3 Combi

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