National Pipe Thread (NPT)
National Pipe Thread (NPT) is a United States standard for tapered threads used on threaded pipes and fittings. In contrast to straight threads that are found on a bolt, a taper thread will pull tight and therefore make a fluid-tight seal. All pots, ball valves, thermometers, and other kettle accessories sold by AIH are NPT.
When sealing NPT fittings into your kettle, you should use Teflon tape. To use the Teflon tape, wrap the threaded portion of your fitting counter clock wise. You should make three rotations on the fitting. After applying sufficient tape to the threaded portion of the fitting, thread this into the pipe. The tape acts as a lubricant and does not need to be over tightened. Teflon tape ensures a seal while not over tightening a ball valve or thermometer while leaving them in a satisfactory position. Do not back off to straighten a fitting. If you go too far, take the fitting off, re-tape, and start over. If you feel you need more tape, add that with your second round.