High Lockout
E39 on Vokera Condexa Pro

Your boiler has lost connection with a safety sensor that monitors the temperature of the exhaust gases, causing the system to shut down for protection.

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

Flue gas probe open

What causes this fault?

This fault occurs when the boiler's control board can no longer detect a signal from the sensor responsible for monitoring the heat of the exhaust gases. The most common reason is that the sensor has developed an internal electrical fault or the wiring connecting it to the main computer has become loose or damaged. Because the boiler cannot confirm the exhaust is at a safe temperature, it shuts down immediately to prevent internal damage.

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

E 38View →

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