Hey, moved in 2 weeks ago and this is my first pool, so this is my first post!
When I turn the valve in front of the pump towards the cleaner the pump sucks a lot of air. When it's split between the cleaner/skimmer I get the odd bubble in the top of the pump filter and a few out the returns. I tried submerging the cleaner robots hose but that didnt stop it sucking air.
When it's sucking air there is a knocking from the pipe connecting to this cap, even when its only pulling a small amount of air.
I took the pump cover off to let the pressure out and tried unscrewing the cap. It gave a little but I didn't want to force it.
Could this be the source of the air leak? What is it for?
Am I ok to unscrew it and inspect it further?