Medium
Er 08 on Biasi Activ A

Your boiler is struggling because it has lost the signal from an outdoor thermometer that helps it adjust your heating based on the weather.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Faulty external temp. probe NTC

Shared across the Activ A range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

Er09View →

All 31 fault codes on the Activ A

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

01E02E03E04E05E06E08E09E10E11E14E15E16E17E18EErEr 01Er 02Er 03Er 04Er 05Er 06Er 09Er 10Er 12Er 14Er 15Er 16Er 17Er 18

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