Medium
E786 on Navien NCB-40LDWE

Your boiler's front cover is not properly attached or secured, which acts as a safety disconnect to prevent the unit from running while it is open.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Improper front panel

From this model's manual
Verified against the Navien Ncb 28ldwe installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Switch off the power to the boilerRemove the front cover and ensure no wires are pinchedReplace the front cover, ensuring it is flush and firmly locked in place with all screws tightened

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