I have an older Hayward sand filter that I picked up used to run on my intex agp. I got it all plumbed up and running for yesterday and noticed that i had a bit of a leak out of the backwash port while it was filtering. After a little research, I figured it was the spider gasket, so i promptly pulled the top of the multi port off and sure enough, the old gasket was really beat up. I just finished putting the new one in, replaced all the bolts and now when i set it to filter and turn the pump on, the filter makes a howling noise and the selector handle depresses itself and water POURS out of the backwash port. I've taken the top off the multi-port and checked the spider gasket and it seems to be seating ok and i really cant see what would be causing this.
Does anyone know what could be causing this???