I just finished repairing a broken elbow on a 2" PVC line that returns water to the pool through an Aqua Genie skimmer. The pool is three years old and the line is about two feet underground. The break was beneath the concrete pool deck which made it difficult to repair. The pool equipment is pretty far (~50') from the pool, so there's a pretty long run of PVC before the water made a 90 degree turn up into the skimmer. I have no idea how or why this elbow cracked other than possibly just a defective piece of PVC. If that's the reason, why did it take three years to break?
When I discovered the leak and broken pipe, I was looking for a problem on the suction side that was causing my pump to not prime. Despite my best effort changing the pump cover gasket, lubing the gasket liberally, and applying a silicone bead to the pump inlet piping, I couldn't get the pump to prime. Now that the broken pipe is repaired, the pump primes fairly easily.
It doesn't seem to me that the broken pipe on the return side of the pump would affect the pump's ability to prime, but I must be missing something. Could someone please help me solve these two mysteries? (1) Why did elbow break and (2) why did repairing it allow my pump to prime. Thanks!!