It looks as though the valve could be taken apart to be inspected. I would do that first just to see if it is in good condition.
It is hard to tell if the pump lid gasket is in good condition or not from just a picture. Look for any cracks in the gasket. Also check the drain plugs, they can leak too. If you have any pool lube, you can use that on all the gaskets for a better seal.
I do not know what you are referring to as the drain plugs? A google search seems to show them as being a part of the filter but wouldn't that be on the discharge side of the pump so how could that impact air in the pump? Also, going to pull apart the Jandy valve now. Would it be best to go to a plumbing supply store to get replacement gaskets and the lube or can all of this stuff be found at a pool store such as Pinch A Penny?
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