High
E48 on Vokera Condexa Pro

Your boiler has detected that the exhaust gases are getting too hot, causing the fan to run at full speed to protect the system from damage.

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.

What the manual says

Manufacturer manual

Flue gas probe error for having exceeded the temperature limit (with this error, the fan operates at max.)

From this model's manual
Verified against the Vokera Condexa Pro installation & service manual, page 57.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the internal sensors detect that the exhaust gases have reached a dangerously high temperature, which is often a sign that heat isn't being transferred effectively to the water. The most common reasons are a heavy buildup of limescale or debris inside the heat exchanger, or a physical blockage within the flue pipes preventing proper ventilation.

This issue often comes to light during the first cold spell of autumn or winter when the boiler is required to run at maximum output for long periods.

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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