1950's Radiant Floor In School

Magnehelic

Hi guys.......need a little help.  We take care of a 1950's Construction church/school that has radiant floors throughout every classroom and in the gym........it is MOSTLY working great, and the only leak we've experienced so far (it is copper pipe embedded in the slab......first wrapped in black sheathing) was last year........and thank God the priest agreed it was better to find and fix it than to start abandoning loops.  However.......we have really begun tearing into this thing now because there is a proactive principal at the school.  We just went through and rebuilt several Herman Nelson Steam Unit Ventilators.........and have attempted to get all the floor loops up and running (there  were 3 classrooms that didn't work......we were able to get 2 of the three up and running just by replacing the high vents on that circuit).  The last one is in a room where they carpeted over the little access plates that on the prints show a "balance and air" valve.  Once I gained access to the prints (mostly ruined laying in a basement that had flooded) I could tell where to start looking for the valve.......and just so we'd know what they looked like and how they operated, I went to one that was accessible.........in an area that they had LONG since abandoned the heat in the floor (just happened to be the principal's tiny little office) 

 What I saw for this valve was a brass hex fitting that was in line with the tubing, that had a screwdriver slot in the middle of it, and a little pinhole in the top of the brass near the ouitside of the top (looking down on it like I was the screwdriver).  Well........it did look familiar.......I have seen valves somewhat like these that were on return lines from heating zones in old houses that were built in the 60's, and all I know is that if you turned the screw perpendicular to the flow, it would shut the zone off.  The little office had it set exactly that way......and when I turned the screw parallel to the flow......Wallahh.......principal now has heat.  What I don't know yet is how the "air valve" part is supposed to work.  My guys have said that they can remember turning the screwdriver on one or two of these......and water coming out of the pinhole momentarily.......but 99% of them neither air nor water came out.  I can snap a picture of one later this week......but was wondering if these "balance and air" valves ring a bell with any of you??  I'm actually thinking that the air part is simply unthreading the brass hex part (packing??)  Any takers??  I drew a liitle picture of what I saw.......laying upside down in a closet.......with a flashlight in my teeth.....



Thanks in advance!!



Don

Magnehelic

Pic didn't upload.....here I'll try

again