Pump not drawing/won't prime

[aylad]

Don't know about all the plumbing, but one thing to check is the spider gasket in the multiport valve. Mine has to be replaced every couple of years because it gets all crumpled up, and when it does that, I get a very small air leak that I only notice when the pump is off for more than 12 hours or so, but it does drain my pump basket after about 12 hours. I don't notice the leak at all when the pump is on. It's a pretty quick fix with a $12 gasket. It would be worth checking.

Janet

[Poconos]

Ed,
That drip you mention is on the pressure side. Won't affect the suction or the ability to prime but it could be the reason the water drains out when the pump is off. In any plumbing situation the fewer bends the better. Each change in direction adds more flow resistance whether it be on the pressure or suction side. The number of bends on either side won't affect the ability to self prime, only add more resistance to flow once water starts flowing. As for isolating things when you replumb you have two options. You can add Unions which allow you to disconnect components but they do nothing to reduce noise and physical stress on components. My solution was to use straight sections of auto radiator hose to connect PVC sections. Nice thing is they allow for some movement between parts and the hose does hold up real well. I've been using the same hoses for years now and are just starting to show some deterioration on the inside but should get several more years out of them. Radiator hose is reinforced and designed for high temperature and adequately high pressure and the pool environment is very easy on them. Ypu can get 3 foot straight sections in various diameters at any good auto store. Buy the cheapest you can. Some are super thick and overkill for this application.
Here's a couple past threads with some pics. In the one you can sort of see the other hose sections behind the filter.

http://www.poolforum.com/pf2/showthread.php?t=6156
http://www.poolforum.com/pf2/showthread.php?t=7054

Al