Does the solar valve ever fail?

I am wondering if the solar valve, specifically the check valve inside of it, has ever failed on anyone with a solar system. Mine is operating properly and allowing the system to drain but then it doesn't stop, allowing a whole bunch of air into my system.

See my saga at the post below:

http://www.poolforum.com/pf2/showthread.php?t=2205

I think I'm goint to push the solar company to replace the innards of the valve.

I have gotten no responses, I hope you don't mind the repost.