started working in a new building recently, they use "carrier digital constant volume" mixing boxes with "price" electronic controls. First problem is finding the controler software, second is the control to vav boxes seam to use a grounded common to activate the fan and heat stages. with only partial schematics, missing covers, and a "bundle" (i'm trying to be nice) of wires that don't fit in the boxes anyway. it seems my first visit was a "get a list started" adventure. Price and UTC were no help on-line tonight. a push in the right direction would be appreciated, thanks.