We just installed a new lawn pump. We were a little confused with the electrical diagram so we hooked up the wires the way we thought it said. The pumps runs but we can not get it to prime. Is it possible for it to be wired wrong and still run( maybe the impeller is going the wrong way) but not prime. We thought we should have the answer to this before we re-plumb it because of suspicious air leaks. Thank you.