PERKO type door closers-adjustment

[serry2706]

I have recently moved into a newish house,and all the doors off the hallway have a chain at the hinge side of the door. This closes the door automatically, but the tension is so strong that twice I have caught, and badly bruised my fingers, once a visiting child, and almost decapitated the cat a number of times!
I've looked on the net, and discovered it is a Perko (or similar) fastener. I was considering just disconnecting them, but then thought this may invalidate my house insurance in case of fire.
Could anyone suggest how I loosen the tension- I need step by step idiot proof instructions- and is it something I could do myself, or would it require 2 people: does it require a tool (if so what is it called and where would I get one) or is it best left to a professsional?
Many thanks for any advice- Julia

[allan the locksmith]

To adjust these you need to undo the plate attched to the frame and twist the chain around to slacken it off.
That sounds easier than it is in reality though. First up see if you can get a nail or something to go through the chain link if not use some mole grips.You basically want to make it so the chain is extended and cannot move back into its case.Once you have it secured then undo the plate holding it to the frame.Now unwind it a little to slacken off the tension then re-attach to the frame.

[serry2706]

[quote="allan the locksmith"]To adjust these you need to undo the plate attched to the frame and twist the chain around to slacken it off.
That sounds easier than it is in reality though. First up see if you can get a nail or something to go through the chain link if not use some mole grips.You basically want to make it so the chain is extended and cannot move back into its case.Once you have it secured then undo the plate holding it to the frame.Now unwind it a little to slacken off the tension then re-attach to the frame.[/quote]

Many thanks for that Allan. Will do them at the weekend.
Julia