If you want to skip to the chase here it is: The experiment failed, but it probably didn't have to.
CPVC vs. PVC: Polyvinyl chloride, abbreviated as PVC, is used for the drain lines, drain vents, sewer lines, and some water supply lines for applications such as sprinkler systems. Chlorinated polyvinyl chloride, abbreviated as CPVC is a thermoplastic produced by chlorination of PVC. CPVC can withstand higher pressures and temperatures than regular PVC, with an upper temperature tolerance of 180 degrees in fairly high pressure applications; so it can be used for hot water pipes. It's cheaper than copper pipe and easier to install. I figured this would make it an ideal pipe for my homebrew setup. It would need to withstand temperatures as high as 212 (boiling) but low pressures (only what a March Pump could push.)
I used CPVC to plumb the whole system, including CPVC ball valves. Things went well for a while.
After a few batches, the CPVC ball valves started getting a little temperamental. After a few more, they started falling apart. I think the problem was residual wort that got in behind the valve mechanism, so even though I rinsed the system thoroughly, there was a little sticky sugar residue. The valves were getting stuck, but loosened up after I turned them on and off at the start of the brew day. There is a little clip that holds the handle onto the shaft. Those clips started popping off when too much pressure was applied to the valve handles. Finally, one of the valves stopped turning at all.
The vise grips seemed like a good temporary solution that would get me through the brew I was currently working on. Nope. The shaft would turn but the valve wouldn't turn on. I had to go back to a completely gravity-fed solution, which meant lifting seven gallons of hot wort up to chest level. Not so much fun. I'll be re-plumbing the system before I brew anything else. The pipe and connectors seem to work well, but the valves should be metal.