AristonClas One Combi

Select a fault code

101Ignition failure🔄 Try Reset

The boiler has failed to ignite after the maximum number of attempts. Common causes include low gas pressure or a faulty ignition electrode.

102Flame signal fault🔧 Engineer Required

A problem with the flame detection circuit. The ionisation electrode may be dirty or damaged.

103False flame detection🔧 Engineer Required

A flame is being detected when the burner should be off. This indicates a gas valve or ionisation fault.

104Safety thermostat tripped🔧 Engineer Required

The boiler has overheated and the safety thermostat has cut it out.

107Fan fault🔧 Engineer Required

The fan is not operating at the correct speed. Safe combustion is not possible.

108Overheating🔧 Engineer Required

The boiler flow temperature has exceeded the safe operating limit.

109Overheat thermostat fault🔧 Engineer Required

The overheat thermostat has detected a fault or the boiler has reached dangerous temperatures.

110Flow sensor fault🔧 Engineer Required

The flow temperature sensor has failed or is reading an incorrect temperature.

111Return sensor fault🔧 Engineer Required

The return temperature sensor has failed.

201Low water pressure🔄 Try Reset

The system water pressure has dropped below the minimum operating level.

205Pump fault🔧 Engineer Required

The pump is not operating correctly.

206Gas valve fault🔧 Engineer Required

A fault has been detected on the gas valve.

301PCB / electronics fault🔧 Engineer Required

An internal fault on the boiler's main circuit board.

501Condensate drain fault🔧 Engineer Required

The condensate drain is blocked or the condensate pump has failed.

🛡️

Protect against future repair bills

Boiler cover means no surprise costs when things go wrong

Prices shown are indicative — actual cost depends on your boiler age and policy type.

Compare repair costs →

📞 Ariston Direct Support

Gas Safe Register
🔧 Find an engineer
gassaferegister.co.uk ↗
Gas Emergency
🚨 0800 111 999
Free, 24/7 — if you smell gas

Phone numbers are provided in good faith — always verify on the manufacturer's official website. PlumbingAdvice.co.uk is not affiliated with any boiler manufacturer.