I am a home owner who had unfortunately installed dorma door closer and engaged SNK door contractor to install my doors. The dorma door closer spoils really easily and after 2-3 years of use, it failed me. When I requested them to come down to troubleshoot what went wrong, they tell me to rip out the original door closer and reinstall a new one at full cost. This is even before try to find out what is the problem. For your info, such door closers are not lasting at all. It is a total waste of money installing this.
In the end, they admitted that only one spare part is spoilt and there is no need to change the whole door closer. The salesman who tells me to install a new one is a creep.
But the installers came and did more damage than good. First they scratch the arm with their plier, then it causes serious misalignment to the door.
When contacted, the Dorma installer said it was not as fault - which in the end I found out it was the door closer causing the misalignment. They insisted I call the door contractor - which is SNK door also known as S&K door or SK door to realign the door.
It was a huge mistake, cause the door contractor ripped and cracked my door frame with his foolish hands. And the boss at SNK door refuses to send his other workers to rectify my issue for me and called me names on the phone. Can you imagine how I as a consumer would feel?
Moral of the story - do not engage these two companies.
Photos of the damage can be found on my blog here
http://www.woollycroak.com/2016/06/bad-review-of-dorma-and-snk-solid-wood.html