I have a new pool at our vacation home that I was closing/winterizing at the end of the summer. Everything went great until I tried to blow out my lines. My pool equipment is on a stand about 5 feel above the pool so there are check valves on the lines going from my pump to the skimmer and the main drains so that my pump won't lose prime so far above the pool. When my shop vac wasn't able to produce any bubbles at the skimmer it finally occurred to me that the check valves would keep air and water from going that direction back to the pool. What do people do? Should I take apart the check valves and manually move the flap? Is there an easier way? Thanks so much for any help with this!!