Start by placing a rinsed, beer-clean glass at a 45° angle under the faucet, open the tap all the way, and…
No beer is coming out. When troubleshooting, always check the most obvious thing first. Is the keg empty? If it is, you will feel a rush of gas coming from the faucet as gas escapes from the keg through the line. Is the coupler on the keg correctly? Is the carbon dioxide tank connected, is it full, and are the toggle valves open?
Flat, headless beer comes out. The head goes away too quickly or doesn’t form to begin with. Check the regulator gauge for proper setting. Is the beer glass clean? If the head forms, then quickly disappears, the chances are that the glass is to blame. Head on beer is quickly destroyed by oils, so greasy food and lipstick can ruin beer foam. Did you pour properly? (At 45 Degree angle with 1/2 an inch to an inch from the faucet, pour until about half way full then tilt glass straight up for rest of pour.)
Foamy, over-carbonated beer comes out. Is the keg empty? Is the regulator set to the proper pressure? Is the keg storage temperature at the proper temperature of 36° to 40° F? Has the keg had time to settle? Did you open the tap all the way? Is the coolant cold enough? The glycol reservoir for the coolant should stay right around freezing, plus or minus two degrees. (27-28)
The beer starts out fine, but then the line “burps.” There is a warm spot, kink, pinhole, soil deposit, or bad seal somewhere between the keg and the faucet. A full keg might be sitting on the hose in the walk-in, crimping the line. Get the lines cleaned. Check insulation and seals.
The beer doesn’t taste right or is darker than usual or cloudy. Have the lines been cleaned recently? Beer lines should be cleaned at least every three weeks. Are the glasses beer-clean? Is air being introduced to the beer somewhere? Check the expiration date on the keg.Has the keg been tapped for more than three weeks? Is the keg getting warmer than about 45° F during storage? (This should theoretically never happen here.)