A customer in Windsor got in touch because the front door would no longer stay closed on the latch unless the lever was lifted.
Testing showed that the multipoint mechanism itself was otherwise operating normally. The problem was that the latch was not springing fully back out when the handle was released.
I removed the multipoint mechanism from the door and opened the gearbox.
The fault was immediately obvious: the spring responsible for pushing the latch back out had broken.
Rather than replace the complete gearbox, I found a spring of similar size and length and used it to repair the existing mechanism.
After rebuilding and refitting the gearbox, I tested the latch, handles and multipoint system. The latch was returning properly again and the door could stay closed without having to lift the lever every time.
