This site has been a Godsend. Last summer I bought a home that came with a pool which was installed in 1980 and I have overcome numerous age related problems thanks to TFP. Although I have been reading and using this site for almost a year, this is my first post.
My current seemingly unsolvable dilemma is that my pump will not prime and I cannot find an air leak if that is the problem.
For some background, I am off to a late start opening the pool. I got everything put back together and started the pump but it would not prime. It has always been slow to prime and last year it always had some air in the pump basket. I worked at it for several hours doing all the plumbing diagnostics recommended on here. I could not find any suction leaks. I was about to give up for the night and then for no apparent reason it slowly started to trickle in and primed and started pumping away. It worked for about four hours and then I had to clean the basket so I opened it up and I was not able to get the prime back after cleaning it out.
At this point I was convinced it was a lid leak. I greased the seal. No prime. Then totally removed the seal and thoroughly cleaned it and smeared grease all over everything that looked like it would benefit from grease. Still no prime. Next I took the seal out and degreased it and everything else and glued it back in with RTV form-a-gasket and then glued the lid down on the gasket. Form-a-gasket was gushing out all sides. When that did not fix the problem, I unmounted the pump and turned it over to submerse the lid seal. It did not leak.
Next I turned my attention to the plumbing. The system was plumbed with poly pipe, barbed fittings, and clamps and the pressure side has sprung leaks on several occasions. Even though I could not find a suction leak, I was now totally convinced it was a loose fitting somewhere so I replaced all of the above ground plumbing to and from the pump with PVC. Still no prime.
I decided to water test the suction side. I plugged the line in the skimmer and filled the pump basket to the rim and let it set overnight. It leaked water out to below the suction inlet and there was water coming out at the junction of the pump body and the motor.
Now I was convinced it could not prime because the pump was sucking air in through the pump internals somewhere. So to test the pump, I unmounted it and installed a short section of suction pipe and put it directly in the skimmer. When I turned on the pump, it was shooting water like a fire hydrant and I mean it was spraying a stream of water all the way to the neighbor’s yard.
Next the only thing left that I could think of was the underground. I plugged the suction side again in the skimmer and filled it with water to the top of the pipe. The water level never dropped at all. Not convinced with that, I decided to pressure test it with air. I blew out the line with a shop vac and plugged it underwater in the skimmer while it sprayed water in my face. I rigged up a pressure test setup and pumped 30 pounds in it. It held for about 5 minutes and then my plug in the skimmer shot out like it was shot from a gun and was never to be found. I got another plug at Home Depot and weighed it down in the skimmer with bricks to avoid another incident. This time I put in 15 pounds of air and it never dropped pressure one bit over about 4 hours.
So now I am left with no prime since Friday. No apparent suction side leaks in the plumbing all the way from the skimmer to the pump inlet. The lid has been completely glued down with RTV. The pump does have an internal leak somewhere but it does work at watering the neighbor’s yard when it has a 2’ long suction pipe. Still no prime when it is hooked up like it is supposed to be.
What should I try next?