Medium
A77 on Vokera Unica

Your boiler has detected an issue with its low temperature safety thermostat and needs to be reset, though you will need an engineer if the error keeps coming back.

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

Low temperature thermostat fault - Reset; if problem persists, call engineer

Shared across the Unica 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.

DIY fix possible

Locate the reset button on your Vokera Unica boiler control panel.Press and hold the reset button for a few seconds to clear the fault.Wait to see if the boiler fires up normally; if the code returns, do not attempt further fixes.

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Related fault codes

A76View →A78View →

All 19 fault codes on the Unica

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

_CL_St(cid:31)A01A02A03A04A06A07A08A09A11ACOAdjAUTOSTOPHoursPP blinking

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