My pump is losing prime over night. In the AM, after the pump is off for the night, the water in the strainer basket is below the outflow discharge of the pump. There is no evidence of water around the tank. The suction side is fine, as I tested all connections and when the pump is running have no air coming in from the suction side. Filling the strainer basket with water the pump immediately draws water and flows fine. I did notice a slight crack at the valve from my Hayward DE filter to the waste hose at the bottom of the filter, although could not find any evidence of water. Could air entering into the system from this source when the pump is off causing the skimmer basket to empty?
What is the model of the filter? Does it have a multi port valve?
Hayward Perflex EC75. I might have found the problem. After trouble shooting all morning, there is a small air leak coming from the strainer basket drain valve. The female end of the drain port is slightly ridged so that the male plug does not tighten down fully,. Little air gets in with the pump running, but when I shut the pump down a small bubble comes us every 10 minutes or so. Guess letting the pump sit for 12 hours over night seems to be enough to break vacuum forcing water I don’t know where (the filter tank?)
Teflon tape did not work, nor did a rubber o-ring gasket. The plug catches, then turns rather than tighten. Short of replacing the pump, any problem with using plumbing compound on the plug to seal the leak? Might makle draining difficult, but that is is winter closing problem.
The ec75 has a bump handle rather than a multi port valve. I don’t know if the bump handle top has a spider gasket or not.
With the filter running, check the waste/backwash line and see if there is a trickle of water coming out.
Maybe one of the service guys can give you an answer about using plumbing compound.
Plumbing compound did the trick. Apparently the seal was letting the slightest air leak - almost undectable until one removed the strainier basket to clear view and then saw the occasional bubble from the plug.
Thanks for the update, that is great to hear!