50-70 (ll-ll) High

Ariston 50-70 (ll-ll) Fault Code

Also written as 5070LLLL — same fault.

The Ariston 50-70 (ll-ll) fault code means: your boiler is currently unable to provide hot water because it is having trouble reading the temperature of the water coming from your taps.. It appears on 4 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: D.H.W.thermistor faulty (short circuit)
Typical repair cost £120-220 (including labour)

Engineer required

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

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Ariston models that show the 50-70 (ll-ll) fault code

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

Source

Ariston 50-70 (ll-ll) 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