High
E09 on Ariston ACO 32 MFFI

Your boiler has detected an internal temperature sensor issue, which has safely stopped the heating from working to prevent any damage.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Heating return temperature probe in short-circuit

From this model's manual
Verified against the Ariston/Ariston Genus Premium Combi installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

E07View →E08View →E10View →

All 24 fault codes on the ACO 32 MFFI

Seeing a different code? Every code this model can display, in one place.

A01A02A03A07A33A97A98A99E04E05E06E07E08E10E20E30E31E33E34E80E94E95E99

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