High Lockout
0A30 on Alpha Pro Tec Plus

Your boiler is struggling to detect the flow of water because of a faulty electrical connection inside the unit, meaning it will likely refuse to heat your water.

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 sensor short circuit.

What causes this fault?

This fault occurs when the electrical component responsible for monitoring the temperature of the water leaving your boiler develops a short circuit. The most common reason is that the sensor's internal casing has failed or moisture has entered the electrical connector, causing the boiler to shut down for safety because it can no longer track how hot the water is becoming.

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.

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Related fault codes

0A31View →

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