High Lockout
con on Vaillant ecoTEC plus

Your boiler's control panel and its internal computer are not talking to each other, meaning the unit cannot receive instructions to provide heat or hot water.

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

NocommunicationwiththePCB: CommunicationfaultbetweendisplayandPCBintheelectronicsbox

What causes this fault?

This fault occurs when the data link between the boiler's control screen and its main internal computer is broken or interrupted. The most common reason is a loose wiring connection or a component failure caused by a power surge or natural wear and tear. Without this communication link, the boiler cannot process your heating requests and shuts down for safety.

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

F.49View →F.70View →

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