without knowing anything else it is a guess. but a regular problem and a standard answer. the temperature in the beer line within the tower is too warm. look up tower coolers. get one. ask the guy who sold you the unit at Bed Bath and Beyond, he'll tell you. you pull a faucet. a tap is something else. no worries. Cheers.
Here is a list of steps for trouble shooting. 1) watch how the beer pours and fills a glass. A burb of foam at the get go that clears up as you draw from the keg can mean either low pressure, or the beer is too warm. Fast shooting foam that never stops either means you have the pressure too high, the temp of the beer is high, or a combination of both. Really watch how the beer fills the glass, if the beer pours quick foam then becomes clear and the head just floats on top then most likely its either low pressure/warm beer. If the beer pours clear then foams up when it hits the glass and the foam dissapates rather quickly it means you are slightly over carbed 2) check the beerline for what you are seeing in the pour. If you don't have clear beerline I suggest you get it. Being able to visibly see the gas forming pockets in the line allows you to know if your adjustments are working. 3) Check your temps! Use two forms of gauges because you really need to forms of conformation. Check the temp of the beer after it's poured, check the temp of the cooler, and the tower(if you have one). Beer should pretty much always be at 38 F or lower but not freezing. So if your temps check out then you have to assume its either system pressure or restriction balancing. And as Bill said, if you don't have a tower fan with a tower kegarator then you will get warm beer, i.e. foam. If the air is static inside the tower it isn't being cooled.
