Background: I have an in ground pool and spa system, about 10 years old. The pump, a PacFab Challenger High Head 2.5hp unit, sits 5 or 6 feet above the pool level due to the slope of the backyard. It has always been a little fussy, because everything has to be just right to get it to pull a vacuum on the suction side, especially from the pool (the hot tub sits several feet higher than the pool). I have a check valve on the pool suction side near the pump, and that helps some, but not a lot.
Problem: Over the years, I've re-sealed the fittings on the pump (filter inlet and pump outlet) several times, and have replaced the fittings once or twice. They have never fit properly (snugly), and I've always had to use a huge amount of teflon tape to get them to seal. They just bottom out in the threads. If I get them to seal, eventually they work loose again. I've tried pipe dope, that didn't work either. I've tried o-rings on the fittings, no dice.
What's next - JB Weld?
I seem to recall testing a new fitting on a new filter housing in a pool store last year, and it fit nearly bottomed out as well. Is this a known problem with the PacFab pump system? If so, any suggestions on a pump that is really good a pulling a vacuum, can run a spa and clean a 20k gallon pool?
Thanks - I'm at my wits end.