air in rodi system

[fot80]

I have set up an RODI system in my basement and I have done all the plumbing myself.  I'm going crazy and I need someone smarter than me to help me remove air from the system.  From what I have observed and tested so far, the system is water tight, but not air tight.  I have no idea where and how air is getting into the system.  It's particularly annoying because if I don't use it for a few days, the media dries up and I'm not sure this is good for it.  I have included a photo.  It looks confusing, but this is the system explanation:

1. Pex tubing for hot and cold going to thermostatic mixing valve

2. mixing valve to split between hose(to fill non rodi water) and timer (in case I forget to turn off the system).

3. timer goes to RODI system

 

As you can tell, there is ALWAYS an air bubble up top, even when i try to bleed it.  Also, I do not see any air traveling in the tubing pre sediment cartridge, so I'm pretty sure it's somwhere in the RODI system.

[slowngreen]

@AZDesertRat

[RayWhisperer]

Every one I’ve ever had, had more air in the DI chamber than that. Everything after the ro membrane is low pressure/low flow. The chamber will drain down after the system is shut off. The only way you’ll prevent this is with a petcock at the outlet. Closing that off will prevent it from draining. However, I think you’ll always have air in the DI chamber.