Solved the puzzle and I have no idea how

[william_shakes_beer]

Last night I was swapping around some kegs, removing empties and placing new kegs in line for fermentation. One of the kegs refused to accept the gas line. The fitting would push down but not lock in place. It pushed itself back up again like the pressure on a return spring. I tried the gas line fitting on another keg, it worked fine. I tried another gas line fitting on the problem keg, no go. I pulled the PRV on the problem keg to reduce the pressure, no go.

This afternoon, I went down and tried to plug the keg into gas again. Went on like usual

Anybody have any explanations to offer? FWIW, it was a wee heavy that brewed 3 years ago. It has been stored in the basement at a seasonal steady 62F. When I pulled the PRV there was no foaming, suggesting there was nothing untoward inside the keg. The only differences I can identify between yesterday and today are: 1.)The keg has been chilled for 24 hours. 2.) I pulled the PRV and dropped the pressure before giving up last night.

 

[day_trippr]

You were drinking?

 

[william_shakes_beer]

No maybe that’s the problem

 

[bracconiere]

my old ball lock QD's need to be pushed closed....push em down then push the balls into lock....

 

[bkboiler]

sounds like u had the posts swapped. Posts with a small notch on the wrench flats at the base are gas posts...
They can be threaded onto the beer side...but will not accept a beer QD.
WHAT A SYSTEM!

 

[Vale71]

Sounds exactly like what happens when you try to attach the gas QD to the liquid out post.

 

[william_shakes_beer]

I thought about that. However, the next day i put the same QD on the same post without issue. Also I pushed down manually on the poppet to see if the PRV wasn't fully releasing the pressure. It released a small amount of pressure indicating the bottom of the tube was above the liquid level ( a gas post not a liquid post) Perhaps I need to disassemble the QD and see if the there is something preventing the balls from grasping the post groove. Perhaps debris in the return spring?

 

[Vale71]

Only thing I can think of is that the QD's poppet had become stuck thus preventing it from latching onto the post...