Just got stuck ressuecting a mammoth unit the other day.The unit itself is in decent shape, retains all its original controls, and hasent (suprisingly) been raped and a subject of modification. My problem is this. It is a package unit, water cooled. Turn it on, close all switches, take it outta morning warmup, and drop the setpoint on the 7100 to 40*. All six stages light up. And heres where I get lost. There is no technical lit on the unit, just the wiring diagram. From that I can tell stages 1&2 on the 7100 energize the liquid soledoids, and I know that of the other 4, 2 of them are for the compressors. The unit trips on high head, this would be due to the condenser water valves not opening.
Here is my big question, are two of these stages for the water valves? If so, I can understand that, but what about the part of the print that shows the wiring on these valves going to the Economizer terminals on the W7100. Thats DC voltage, right? The valves are the Honeywell Modutrol. It just says 24V for power. If Im not mistaking, this unit also has a free cooling coil tied into the same lines, kinda like a bypass. I got tomorrow off, so, if anyone has an idea, or experience with these, drop me a line. It would really be appreciated.