Insufficient System Pressure High

Ariston Insufficient System Pressure Fault Code

Q: What does the Ariston Insufficient System Pressure fault code mean?

Your boiler has switched itself off because the water level inside your central heating system is currently too low for it to operate safely.

Q: How much does it cost to fix Ariston error code Insufficient System Pressure?

Typical repair cost for the Ariston Insufficient System Pressure fault is £80-150 including labour.

Also written as INSUFFICIENTSYSTEMPRESSURE — same fault.

The Ariston Insufficient System Pressure fault code means: your boiler has switched itself off because the water level inside your central heating system is currently too low for it to operate safely.. It appears on 2 Ariston models in our database.

Technical description: In the event of insufficient water pressure in the heating system (less than 0.4 bar), a safety device will shutdown the boiler.

Typical repair cost £80-150 (including labour)

DIY fix possible

Locate the external filling loop (a flexible metal braided hose) underneath the boiler.Open the small valve(s) on the loop to allow mains water into the heating system.Monitor the pressure gauge on the boiler front until the needle reaches 1.5 bar.Close the valve(s) tightly and ensure no water is dripping from the loop connection.

Find a Gas Safe engineer

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

Gas Safe Register →

Ariston models that show the Insufficient System Pressure fault code

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

Source

Ariston Insufficient System Pressure 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