High
F.87 on Vaillant ecoTEC Plus 625

Your boiler has detected a problem with the internal ignition components, meaning it cannot safely light the burner to provide heat or hot water.

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

Fault: Electrodes. Electrodes not connected or they are connected incorrectly, short circuit in the cable harness

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
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 boiler's control board loses communication with the components responsible for creating the spark and sensing the flame. It is usually caused by a loose connection, damaged wiring, or electrodes that have worn down and can no longer complete the electrical circuit required to start the boiler. Without this secure connection, the system shuts down as a safety precaution to prevent unburnt gas from entering the combustion chamber.

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

All 170 fault codes on the ecoTEC Plus 625

Seeing a different code? Every code this model can display, in one place.

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