High Lockout
Fault 30 / 7 on Worcester Bosch Greenstar CDi Compact

Your boiler has detected a problem with a temperature sensor that controls the heat of your water, which might cause your heating or hot water to stop working correctly.

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

Mixer temperature sensor faulty: Mixer temperature sensor (MF) connected to IPM faulty.

What causes this fault?

This fault occurs when the internal control system loses communication with the sensor responsible for monitoring water temperature at the mixing valve. It is usually caused by the sensor failing due to age or a loose electrical connection between the sensor and the boiler's main control module. When this happens, the boiler shuts down as a safety precaution because it can no longer accurately regulate the heat of the water.

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

C1View →C6View →A7View →

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