How much does it cost to fix Alpha error code 0A16?

Typical repair cost for the Alpha 0A16 fault is £150-250 including labour.

0A16 High

Alpha 0A16 Fault Code

Q: What does the Alpha 0A16 fault code mean?

Your boiler is struggling to heat the water quickly enough, so it has stopped working to prevent itself from overheating.

The Alpha 0A16 fault code means: your boiler is struggling to heat the water quickly enough, so it has stopped working to prevent itself from overheating.. It appears on 3 Alpha models in our database.

Technical description: Flow sensor temperature rise incorrect. The time taken for the flow temperature to rise is too great.

What causes the Alpha 0A16 fault?

This fault occurs when the boiler's internal sensors detect that the water isn't heating up at the expected speed after the burner ignites. The most common reason is a restriction in water flow caused by a failing pump or a buildup of debris, preventing heat from being moved away from the heat exchanger efficiently.

This issue often surfaces in autumn when the heating is turned back on after a summer of inactivity, which can cause the internal pump to seize or stick.

Typical repair cost £150-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Alpha models that show the 0A16 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Alpha 0A16 fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026