High
0A15 on Alpha FMK

Your boiler has stopped working because the sensors that monitor water temperature are providing conflicting or incorrect readings.

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.

Technical description

Flow and return sensor anomaly detected.(incorrect temperature value shown on sensor.)

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.

Find a Gas Safe engineer
Search the official register →

Related guides you might find useful

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →