Installing a Pentair Pac-Fab Dynamo Pump, Strainer Pot Housing

[Msflownder]

I am in need of some guidance on installing the Strainer Pot Housing piece to my pump. My pool is still full and I have not done anything else to the pump. My problem is, if I start taking this apart is water going to start leaking from the pump? I am a complete newbie to owning a pool so any help would be greatly appreciated. I already have the part that I need to replace but why else will I need? Is it difficult to get the piece out. I really am not sure where to start.

[Teapot]

Is the pump above or below the water line?
Is there a valve to turn off the water entering the pump.
Maybe post a picture so we can take a look for you.

[Lauraharp]

I noticed when I turn off pool pump the strainer pot starts leaking. As soon as pump to switched to off position, you can see the lid on strainer pot push up from the change in the pressure. I’ve never had this issue before and not sure of the cause. Any thoughts?

[Teapot1]

Have you cleaned your filter thoroughly? Excess pressure has to escape, it can go forward to the returns or back through the pump, whichever it finds easier.