How much does it cost to fix Alpha error code 71?

Typical repair cost for the Alpha 71 fault is £120-350 including labour.

71 High

Alpha 71 Fault Code

Q: What does the Alpha 71 fault code mean?

Your boiler has stopped running because it senses that even though the burner is lit, the water inside isn't getting any warmer.

The Alpha 71 fault code means: your boiler has stopped running because it senses that even though the burner is lit, the water inside isn't getting any warmer.. It appears on 7 Alpha models in our database.

Technical description: No primary temperature increase detected

What causes the Alpha 71 fault?

This fault occurs when the boiler fires up but the sensors do not detect a sufficient rise in water temperature, causing the system to shut down for safety. The most common reason is that the water isn't moving through the unit properly, often due to a failed internal pump or a blockage in the pipework. It can also signify that the sensors responsible for measuring heat are faulty or that the main heat exchanger is clogged with debris.

This issue often surfaces during the first few cold days of autumn when heating systems are turned back on after being idle all summer, which can cause internal pumps to seize.

Typical repair cost £120-350 (including labour)

DIY fix possible

Check that the radiator valves and the main isolation valves under the boiler are fully open.Ensure your system pressure is topped up to between 1 and 1.5 bar.Try resetting the boiler to see if the error was caused by a temporary air lock.

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Alpha models that show the 71 fault code

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

Source

Alpha 71 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