Ariston · Clas ONE
109 boiler fault code
Clas ONE combi
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What 109 means
System pressure greater than 3 bar.
Gas Safe engineer: Contact a Gas Safe registered engineer to diagnose this fault code.
Renting? Report it to your landlord or housing provider first. They are responsible for gas safety and boiler repairs, and the repair should not cost you.
Safe check
Note the code shown on the display and contact a Gas Safe registered engineer.
When to contact an engineer
Contact a Gas Safe registered engineer to diagnose this fault code.
Safety notice
A boiler fault code alone is not a gas or carbon-monoxide emergency. If you smell gas, a CO alarm sounds, anyone feels unwell, or there is an unsafe flame, leave and call 0800 111 999 from outside.
Source and provenance
- Ariston document 420010818500 · Table summarising error codes, printed p. 34
installation and servicing instructions
Official Ariston UK library copy; document 420010818500