sand pump 3000

Sand filter leaking out of backwash port.

Problem Description

The sand filter is dripping water out of the backwash port even when the valve is set to “Filter.” It’s a steady trickle.

Possible Cause and Solution

A bad spider gasket inside the multiport valve is the likely cause. Over time they warp or tear, and water sneaks past into the backwash line. Replacing the spider gasket should fix the issue.

Additional Tips

Lube the new gasket lightly with silicone pool lube so it seats better. Check the spring in the handle too, since a weak spring can also cause leaks. Turning the valve handle while the pump is running can damage the gasket. Clean the channels really well before installing the new one. Let the glue or gasket settle fully before restarting the pump if the gasket is the glued-in type.