If air is returning into the pool there might be a leak on the suction side of the pump. Check the following items that maybe causing air to enter the system:
- The strainer cover and O-ring. Tighten if loose or replace gasket if damaged.
- Check the level of water in the pool- if it’s low, this may be causing water and air to mix into the skimmer.
- The skimmer weir may be stuck in the up position, causing water and air to mix in the skimmer.
- Check the drain plugs on the pump strainer housing.
- Check all of the threaded fittings for leaks from improper sealants or sealing procedures.
- Check glued fittings for bad glue joints.
- Check all valves for possible leaks. Valve stem O-rings are a common suction leak point.
- Check and ensure the pump is not cavitating.
- Check pump housing for cracks