Red L.E.D. H High

Ariston Red L.E.D. H Fault Code

Also written as REDLEDH — same fault.

The Ariston Red L.E.D. H fault code means: your boiler has switched itself off because the water inside the heat exchanger has become too hot to operate safely.. It appears on 1 Ariston model 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: Shutdown Due To Overheating. In the event that the safety limit is exceeded for the temperature of the water in the boilers exchanger, the thermostat shuts off the boiler and the red L.E.D. H illuminates.
Typical repair cost £90-280 (including labour)

DIY fix possible

Wait 20 to 30 minutes for the water temperature to cool down naturally.Check that your radiator valves are fully open and there is no air trapped in the system.Press the Reset button once the unit has cooled to see if the error clears. If it recurs immediately, call an engineer.

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Ariston models that show the Red L.E.D. H fault code

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

Source

Ariston Red L.E.D. H 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