Sanke Coupler Foaming Issues

[NeoBrew]

I've got a Kegco Sanke-D coupler that I use with commercial kegs when I can't keep up with brewing enough. (Which happens too often lately!)

The coupler I have is this one. Lately I can't get a beer out of the thing without major foaming. If I just pour a pint out I would typically end up with about 2" liquid beer and the rest of the glass filled with foam. After some diagnosis I'm pretty sure CO2 is leaking past the system somewhere and getting into the beer stream directly. There is clearly at least a bubble of CO2 in the coupler. When I go to pour a new pint that bubble is visible in the line and when it hits the tap it causes a huge amount of foam. There also seems to be a small stream of bubbles in the line as I pour, which also all turn to foam when they get to the tap.

I'm using a Perlick tap with the flow control. I have approximately 12' feet of beer line as I am using the same lines I would use for my ball lock Corny kegs. I typically run my system at 12-14 psi of CO2.

I believe CO2 is bypassing the inner rubber seal at the bottom of the coupler. I thought I had this figured out and that I was over tightening the coupler down onto the keg, but that was a fleeting success as the bubbles returned.

Any ideas how to fix this? The seal looks like it is in good shape, but when I push on it with my finger there seems to be some space behind it. Is this normal? Is there a chance that I put the check ball and inner pieces together wrong? I can't seem to find a schematic of what those assemblies are supposed to be like, but I am not sure it could go together any other way.

Any help would be appreciated.

 

[GilSwillBasementBrews]

You could try disassembling the sanke tap and ensuring the o rings and rubbers on the bottoms are in good condition and grease them with keg lube to help ensure a solid seal. Could be pulling in air past one of the seals?? When I had an issue like what your describing when using my sanke tap I just removed it from the keg turn the coupler 180° and re connected and it was ok. If it was a persistent issue I’d definitely be looking for a more permanent solution.

 

[franknbeans]

I've got that same sanke coupler and have the same problems. I ended up turning down the co2 pressure to about 10 from 14 and that made a big difference. I had an amber ale and now a lager currently with the tap. I've completely disassembled the coupler looking for a chewed up oring and couldn't find an issue.. no clue! I still get some foaming, but not like before.

 

[NeoBrew]

I think I made some progress...but literally 1/4 pint after I made the last adjustment my keg kicked!

In looking at some cleaning videos online I realized a detail I didn't understand. Inside the coupler is a check ball and a plastic retainer that keeps the ball in position. The retainer is a three pointed thing that gets held by friction inside the barrel of the coupler. At some point I had pushed that retainer more or less tight down on top of the ball. That's how it was when I started this thread. Then I pushed it up 1/4" or so so the ball had some room to move and let beer through. That made things better. Then I watched this video and saw that they put the retainer way at the top of the barrel so the ball could move up to the top of the barrel when beer flowed.

Unfortunately I have not been able to test it yet. Let me know if you do and if it works.