When we had the big rains last week, I went out and drained 4 or 5 inches of water out of my pool by backwashing a while and pumping the rest to waste. When I was finished, I set the valve back to filter, and water began leaking from the seam in the multiport. Here's a link to a drawing of the valve. http://www.poolcenter.com/parts_valves_ ... 12-147.htm The water was leaking from between parts 8 and 12, which are sealed with an O-ring, item 10.
I disassembled the valve and cleaned everything. I didn't see any sign of a problem. I reassembled the valve, making sure to evenly tighten all the bolts, but it still leaked. Filter pressures were exactly what they always are, and flow to the pool is excellent and just like it's always been. The leaking occurs at all multiport settings. The leak is mostly on the front of the valve, but it leaks most of the way around.
I ordered the gasket and plug assembly, item 7, and the O-ring, item 10, and installed them tonight with only a little improvement. I have the bolts tightened as much as I'm comfortable tightening them, which is tighter than they were originally.
I'm stumped. Anybody have any suggestions?