My swimming pool pump is not functioning proper, no matter what you turn it to, water comes from backwash line

Question

If you turn it to the normal for it to filter is still lets water come out of the backwash/waste line, and I do not know what to do

Answer 1

check the o-rings

Answer 2

One of two things.

1/ The most common is that the key stem gasket inside the multiport ( the dial valve on your filter that you're turning) has either ripped or has torn off the key stem or multiport body. The part is usually cheap ( under 20 bucks for most  but not all filters) but requires a little know how and proper glue, to install. You can either remove the multiport assembly and take it into a pool shop for service or do it yourself. Your call here, but ideally you ought to let a pro handle the whole thing on site. Just let them know the make and model of the filter. That information is on the filter tank label.

2/ Worst case scenario, you had an overheat. Either the heater wasn't shut down 20 minutes prior to the pump shutting down or your pump ran dry for an extended period leading to cavitation in the pump housing and heat transfer up to the multiport. Either way, the multiport being made of plastic, deforms slightly with the excess heat and then the key stem and it's gasket no longer seat properly in the multiport body. The only fix here is to replace the multiport, which is a tad more expensive than just a gasket.

Here's a cutaway of a typical multiport (an old Hayward in this case), but they're all more or less of the same type of construction. Just different locations for inlets and outlets and placement on the tank.

http://www.poolcenter.com/hayward_vafi-f...

What they're calling the valve seat gasket is also known as a key stem gasket. Your's will be one of two types. It either sits in the actual body of the multiport or it is attached to the key stem itself. All depends on the make and model.