The LCN 4041 and 4040XP Backcheck Selection Valve
Door Hardware Geek Eats Humble Pie
Well, I feel pretty foolish having installed several hundred 4041’s over the course of my career and never noticed the “Backcheck Selection Valve” which is located on the back of the closer body, where it is installed against the door or header. But as I always say, “You learn something new every day, whether you want to or not.” Life is learning, and I love life.
Still, the idea that, concerning a door closer with which I am so intimately acquainted, and for which I have so much respect, there was an important fact that I did not know, shook the very foundations of my identity as a Door Hardware Genius. Yet I was forced to admit I did not know. I resolved that I would find out.
Anyway, when this valve was pointed out to me by Jess the Door Closer Doctor, I did not know to what she was referring, so I went to a door that has a vintage 4041 installed on it in standard installation and pulled the plastic over off. There I saw the usual array of adjustment valves (see picture): main speed, latch speed and backcheck. Then I went to a distribution center and pulled a brand new 4040XP off the shelf and found the same array of valves on the front and this “mystery valve” on the back (see pictures).
There was a man there with me who works at the distribution center. He has been in charge of the LCN department for about 25 years. He didn’t know what it was, either. I was glad. It made me feel better to know there was someone as ignorant as I apparently am. I find that if I am an idiot it is always comforting to find someone else who is also an idiot, if possible. Together we looked over the installation instructions that were in the box but could not find mention of the mystery valve.
I then did what all geniuses do when they are stumped by something that is probably very simple. I cried a little and then called tech support.
I find IR tech support in general to be responsive, knowledgeable and friendly, and LCN tech support to be exceptionally so. They quickly solved both the mystery of the valve and the mystery of why I could not find the valve on the instructions. They told me that the Backcheck Selection Valve is for use mainly in parallel arm installation, so it is only referred to in the Parallel Arm Installation Sheet. The Backcheck Selection Valve re-routes the fluid in the closer so that it gets to the Backcheck Valve sooner, because in parallel arm installations the arm must otherwise travel farther before the fluid would reach the valve.
A kind of secret use of this valve, says LCN Tech Support, is when in standard or top jamb installs you want the backcheck to engage sooner for some reason – because of wind or because the wall is at only a forty-five degree angle to the opening, for example.
So that is the skinny on the Backcheck Selection Valve on the LCN 4040XP door closer. Armed with that knowledge I can now go forward with my Door Hardware Genius life, a little smarter… and with just a bit more humility.