I hope the renters didn't get their security deposit back! The one leak you know about is on the effluent side of the pump - if water is leaking out, air can't be getting sucked in there when the pump is running (however, when the pump is off, that leak can kill the prime, but that would only effect the first few minutes of operation) What I usually do is put the o-ring off a threaded plug (SP 1022-C) on the male adapter with a couple extra wraps of teflon tape and only tighten it enough to have the o-ring seal (without pinching so much it looses it's shape/ seal!)
As said, the leak you described would not allow air into the pump while it's running. The usual reasons for air in the pump while it's running are:
1) The pump lid gasket not fully sealing
2)A bad threaded or glued connection (including the winterizing plugs on the pump) or faulty valve
3) Not enough water in the pool, allowing the skimmer (s) to suck air (or a stuck skimmer weir, which would starve the skimmer)
4) A broken suction line underground
5) An obstruction in a suction line causing cavitation
To check anything above ground you can slowly dribble water over any suspect area and watch the bubbles in the pump basket to see if they lessen or go away - if they do, you've found
a leak (sometimes there are more than 1) [I use my free hand to cup the water on the bottom of a horizontal pipe to be sure the water will get drawn into a bottom side leak]
You can pressure test any suspect line to determine if it's leaking.
Obstructions are harder to detect - if you have access to an electrician's snake, you could run that through any suspect pipe to see if it freely passes through (on a long run with lot's of elbows, the snake may not pass through anyway

) Another way would be to run a garden hose from the pump inlet (you can wrap a cloth around the hose to help it seal the pipe) and look for debris being blown through the suction port.
That's the 'basics' of what's probably going on, if you try a few of the things I've mentioned and can't find the solution, let us know (or if I haven't fully explained myself well {it happens more frequently than I'd care to admit

}, I'm here almost every day and I'll give it another shot)
Bookmarks