High Lockout
S.39 on Vaillant ecoTEC Pro / ecoTEC Plus

Your boiler has temporarily stopped running because an external safety device, such as a condensate pump or a pipe thermostat, has detected a potential issue and sent a signal to shut the burner down.

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

Burner off contact has been triggered this could be because of contact thermostat or condensate pump

What causes this fault?

This fault occurs when an safety device outside of the boiler has tripped and told the system to shut down for protection. The most common reason is a blocked condensate pump that is full of water and cannot drain, or a pipe thermostat that has detected the system is getting too hot and has cut the power to the burner as a precaution.

This fault is more frequent during very cold winter spells, as frozen external drainage pipes can cause condensate pumps to backup and trigger the safety switch.

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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