uPVC multipoint lock won't unlock with key from outside

[Londoner]

I thought we had a faulty euro cylinder but I've just swapped it and still have the same problem.

Normally I lock this uPVC door by moving the handle up then down, then inserting key and locking.

To open the door, I unlock with key, push the handle DOWN, then have to turn the key another quarter turn to actually open the door.

Right now, everything works *except* for that last quarter turn with the key.

This is only a problem when coming in from outside. The lock still works as normal when pushing the handle down from inside, and the door opens. Any ideas? Does it mean replacing the whole multipoint lock?

 

[sircerebus666]

The exterior handle is probably worn

Have you tried playing about with it with the door open to see what happens with the locking mechanism ?

 

[Londoner]

The handles seems to be doing what they should do, it's just the specific action of doing that quarter turn using the key from the outside. So I guess it's whatever the enagagement is between the cylinder and that internals of the mulitlock? Locking seems to work fine, unlocking from the inside using the handle works fine. And it's a new cylinder.

 

[sircerebus666]

Did you lock the door with the door open to see if there is any difference between using the inside handle and outside one?

The fact that it works perfectly well on the inside but not the outside suggests the external handle , it is quite common for the handle to go faulty on one side only

Have you stripped off the handles and examined them for differences? Have you got another door you can borrow a handle from ? Or using locking pliers as a handle to see if that makes a difference?

 

[ronniecabers]

As sircerebuss66 says , you need to attempt the motions with the door open , you'll see whether its the ' nightlatch ' thats not opening correctly , or the deadbolt. If its the nightlatch , then remove handle and see if putting a pair of molegrips ( or similiar , sometimes the internal handle can be used for testing purposes ) , and then see if you can turn the spindle to pull the nightlatch back. If not then it sounds like the Multipoint locks gearbox has developed a fault

 

[Londoner]

Yep I checked the handle and it was fine. I could tell the handle mechanism was pretty basic and there was nothing wrong with it, it was only ever that last quarter turn in the cylinder.

In the end I replaced the centre case/gear box and it's now working fine. Something must have failed within the gearbox I guess.