S 05 Medium

Ariston S 05 Fault Code

Also written as S05 — same fault.

The Ariston S 05 fault code means: your boiler is struggling to detect the temperature of the water it is trying to heat for your taps and shower, so it has stopped producing hot water to prevent overheating.. It appears on 4 Ariston models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Short circuit on Domestic hot water sensor
Typical repair cost £120-220 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →
Boiler cover options

Avoid the next call-out bill

A cover plan would handle faults like S 05: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Ariston models that show the S 05 fault code

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

Source

Ariston S 05 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 7 July 2026