Verified boiler fault code

Ariston 108 Fault Code (Cares ONE NG)

Insufficient water; filling is requested.

Safety disclaimer

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Fault code summary

Manufacturer
Ariston
Fault code
108
Fault type
Low pressure, Pressure sensor
Severity
lockout
Reset
The manual says to restore pressure to 1 bar with the filling loop, then press the MODE button; frequent rebalancing requires a qualified technician.
Applicable models
Ariston Cares ONE NG

Quick answer

Insufficient water; filling is requested.

What does this fault code mean?

Insufficient water; filling is requested.

Common causes

  • Insufficient water pressure in the heating circuit.

Symptoms

  • The display shows Err/108 and requests filling.

What can the homeowner safely check?

  • Read the pressure gauge. Follow the manual's filling procedure only if the user is familiar with the installed filling loop.

Boiler reset information

The manual says to restore pressure to 1 bar with the filling loop, then press the MODE button; frequent rebalancing requires a qualified technician.

When should I call an engineer?

Contact a suitably qualified heating engineer when the fault persists, the boiler locks out, or the manufacturer instructions do not resolve it. For gas appliance work in the UK, use a Gas Safe registered engineer.

Engineer diagnosis

  • Check system pressure, leaks, pressure sensing and filling-loop condition.

Applicable boiler models

Related fault codes

Manufacturer documentation

Cares ONE NG - User Manual

Safety shut-off due to insufficient water pressure: Err/108; the manual gives a filling procedure and warns about frequent rebalancing.

Last verified

2026-09-12

Frequently asked questions

What does Ariston 108 mean?

Insufficient water; filling is requested.

Can I reset a Ariston 108 fault?

The manual says to restore pressure to 1 bar with the filling loop, then press the MODE button; frequent rebalancing requires a qualified technician.