I was able to get top big plug out of the air tank.
This tank is 1947 and it looks amazing auto drains work.
It is just under ¼” thick this thing is so heavy.
I could not budge the bottom plug but I am done trying I have seen enough.
The drain in the bottom is 1/2" I like that.
Another home hydro test completed. 300 Psi passed with flying colors.
This time I did not start out with the tank pressurized. The pressure washer had no problem just bumping it to 300 psi. The last couple times is started out with 100 psi basically the incoming water pressure.
I am not sue if that made a difference or the switch is just working better now. Either way it was simpler to do the test when it worked as expected.