Tried everything and still have foam.

I don't homebrew but welcome anyways!

 

Have you shaken the keg up too much?

 

What is the actual beer temp? Below 40 is not a temperature.

 

Welcome aboard, and good luck to your liver! You might want to post your question in the homebrew forum. Lots of knowledgeable folks frequent that one, and I'/m sure they would be happy to help.

 

What is the I/D of the tubing? With 10' of line you might have to go bigger than 3/16" (1/4")

http://beersmith.com/blog/2011/07/14/keg-line-length-balancing-the-science-of-draft-beer/

 

Not sure how this became a home brew question. Sounds to me like he has commercial kegs at home.
Regardless, the theory is the same. You need to balance the system based on the volumes of CO2 of the beer when it was kegged (v/v), the temperature and using a Zahm Nahle or force arbitration chart. 8-10 psi is definately way too low. Most beers will be in the 2.5 - 2.7 volumes. If temp is indeed around 38, then the pressure needs to be in the 14-16 range.

What do the beer lines looks like after they sit for a while - gaps instead of solid beer?

Bigger diameter will further screw him. Adding line is designed to slow the flow, bigger diameter will make it faster.

 

Sorry - autocorrect got me. Zahm Nagle and force carbonation are the charts. Everything else still makes sense. Read any of the threads here regarding foam and you will get the same answer from any of the handful of people who routinely respond to these questions.

 

Yes, but I am assuming (maybe incorrectly) that the OP needs 10' of line and to serve at 8-10 psi,

 

If he is combating foam, he likely added length to slow the flow. IMO for short draw it is easier to balance temp / volumes and adjust pressure to the chart, and ensure you have no breakout in the line. If you still have foam after that, you can then add line to slow the flow and reduce turbulence. Very often the 5' lines that come with a kegerator are too short to allow you to get the pressure up high enough to balance. 8-10 is most likely going to get him flat beer and not be enough pressure to hold the CO2 in solution. We may never know because after he pulled the pin on the discussion he never came back.