Question for clearing pipes connecting air compressor to pump drain hole

[Jaredsdad]

plan to hook up my air compressor to the drain plug on my pump to blow air to clear pipes for closing my pool.
My question is this.

On the suction side, I have 1 skimmer, and 1 drain. My jandy valve allows me to either have the Skimmer on/drain off, drain on/skimmer off, or both ON.
I do not have an option to close both at the same time.

So I’m wondering how I will ensure that I am blowing air into the return side only. My thinking is that even if I air lock the drain, and gizmo the skimmer, that the PSI might be too much and instead of blowing air only through the return side, I will blow out the gizmo. Am I thinking correctly, or should I be worried about that?

 

[Catanzaro]

On the suction side, I have 1 skimmer, and 1 drain. My jandy valve allows me to either have the Skimmer on/drain off, drain on/skimmer off, or both ON.
I do not have an option to close both at the same time.

Very simple. Shut off the main drain and clear the skimmer first. If you lower the water below the skimmer and have a shop vac, you can vacuum the water out of the skimmers while the compressor is doing its job. Then when you are done with the skimmer, close up with a Gizmo. Now shut off skimmer and open the main drain. Turn compressor back on and blow out the drain until you see the bubbling effect, etc. Then close the main drain valve and lock the air in. Remember the skimmer line has been already cleared out and capped off. You are only working with one at a time so the Gizmo will not be affected as the valve is in the closed positon.