2 valve winterizing kit creating air in system

[Mike09]

I'm looking to see if anyone else has had this experience and if they have found an easy way to fix it. My '16 Jayflight 27BHS came with a winterizing hose installed . The in side of the pump comes off the pump and has a t with a valve that draw a from the tank. There is a 6" straight piece then another valve and the clear hose for antifreeze. I have been having problems with air in my system and believe I have narrowed it down to the 6" piece that points straight up. There is no way for the air in that line to purge and replace with water creating an air lock. My initial thought is to get a 3 way valve and replace the 2 cheap plastic ones. I'm wondering if anyone has any other ideas.

I came to this conclusion by drawing water into the clear hose then draining it up to the valve, essentially putting water in the 6" piece . My problems went away . The only problem is that anytime I drain the FW tank with the low point drain, that water comes out.

Any thoughts?