What's the difference between gas-in and liquid-out disconnects?

[TAK]

First, why are there different ball lock disconnects at all for gas-in and liquid out?

Of more practical considerations, say you want to purge a keg from the bottom up. You would want to connect a gas-in disconnect on what is ultimately the liquid-out side. I know the different disconnects don't lock (or at least not well?) onto the opposite designed post. So do you put the gas-in post on the what would be liquid-out side to purge, then swap the post for normal use? Or, do you put a liquid-out disconnect on your gas hose? Does it matter at all?

 

[brettg20]

One is black and one is gray :smack:

 

[brettg20]

Other than that I am not sure other than don't put the wrong one on the wrong valve. I once on accident put a gas disconnect on the out valve and it was a b**ch to get off.

 

[mattd2]

Other than that I am not sure other than don't put the wrong one on the wrong valve. I once on accident put a gas disconnect on the out valve and it was a b**ch to get off.

From what others have said about the "don't put a gas on liquid" I would guess that the gas side post is slightly smaller.
For what the OP is suggesting to do I would say if you haven't bought the QDs yet, get the ones with MFL - that way you can swap gas/beer lines simply by unscrewing the barb and putting it on the QD you want it on

 

[brettg20]

From what others have said about the "don't put a gas on liquid" I would guess that the gas side is slightly smaller.
For what the OP is suggesting to do I would say if you haven't bought the QDs yet, get the ones with MFL - that way you can swap gas/beer lines simply by unscrewing the barb and putting it on the QD you want it on

Yep it is def smaller, it was hard to push it all the way on and also to get it off. First and only time I've ever done that.

 

[TAK]

Yep, I definitely use swivel nuts, mostly just wondering what the difference is between the disconnects, and why.


Oh, and...

it was hard to push it all the way on and also to get it off. First and only time I've ever done that.

That's what she said.

 

[caphector]

When I first started kegging I didn't realize they were different sizes. I eventually had half my kegs assembled one way and half the other.

This resulted in much confusion until I figured out my error.