Emergency
A09 on Vokera Unica i32

Your boiler has temporarily stopped working because the exhaust area has become too hot, which is a built-in safety measure to prevent damage.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Flue thermistor over temperature or flue thermistor counter fault

From this model's manual
Verified against the Vokera/Vokera Unica I28 I32 I36 Installation Manuals Pdf 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 emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Boiler cover options

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Related fault codes

A01View →A02View →A03View →

All 18 fault codes on the Unica i32

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

_CL_StA01A02A03A04A06A07A08A11A77ACOAdjFlame ONHoursPP blinking

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