Why is pool water coming out of the backwash hose while the the pump is set on filter?

Question

I have water running out of then backwash hose as the pool pump is set on the "filter " setting. I'm losing alot of water. How can I stop this leak.?

Answer 1

You should call someone to fix the backwash valve.  Most likely it is not sitting correctly.  It is not completely opening or closing either of the settings, check your flow meter and I bet your gpm is low as well.  You can try working with the valve and finding a spot that will close the backwash down.

Answer 2

For now you need to get some sort of a rubber plug to plug up the backwash line or have a valve installed on the backwash line so you can close it off when in filter mode. It sounds like the spider gasket inside the multiport valve needs to be replaced.