High
E34 on Ariston ACO 27 MFFI

Your boiler is trying to start its internal fan, but a safety switch is not detecting the airflow needed to let the ignition safely proceed.

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

Fan operation but air pressure switch does not close

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

E33View →E35View →

All 24 fault codes on the ACO 27 MFFI

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

A01A02A03A07A33A97A98A99E04E05E06E07E08E09E10E20E30E31E33E80E94E95E99

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