(D) LED turning on High

Ariston (D) LED turning on Fault Code

Also written as DLEDTURNINGON — same fault.

The Ariston (D) LED turning on fault code means: your boiler has switched itself off because the water pressure inside the system has dropped too low to operate safely.. It appears on 3 Ariston models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Boiler shutdown due to insufficient water pressure
Typical repair cost £0-120 (including labour)

DIY fix possible

Locate the filling loop (usually a flexible silver hose) underneath the boiler.Slowly open the one or two small valves on the loop until you hear water flowing.Watch the pressure gauge and close the valves tightly once it reaches 1.5 bar.

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Ariston models that show the (D) LED turning on fault code

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

Source

Ariston (D) LED turning on fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026