I'm helping to run a community pool, run by volunteers from the neighborhood. For several reasons we chose to drain the pool; terrible algae problem, need to make some some repairs and so on. I drained the pool through the main drain with the pool pump, it worked great, but it was getting dark and so, with about 3 feet of water just above the drain in the diving section we shut it down for the night, thinking it would continue to drain during the night.
Needless to say, it did not keep draining. We rented a sump pump and pumped it out, did our cleaning and painting and began to fill the pool.
I went to check on the pool today, and decided to test the pump and drain. I can get no flow through the main drain, so I assume there are two possibilities as to the cause: the drain is clogged up with goop, or there is a vapor lock (air) in the drain pipe. The drain line has to come up from the drain into the pump house, so I kind of favor the air theory.
So the question is, how to fix this? I don't want to run the pump for an extended period of time without water...
Thanks in advance for your help!