Air compressors are capable of driving many different types of time saving tools, for everything from auto repair to carpentry and house painting. Maintaining the correct pressure is the key to your compressor's effectiveness. Two levels require resetting to operate your air tools at maximum effectiveness. The first is the lower pressure limit, or how low the pressure must be depleted before the compressor comes on. The second is the upper limit, or how high the pressure will build before the compressor goes off.
Things You'll Need
Operating manual for air tool
Remove the screws from the plastic shroud on top of the compressor near the air outlet valve. Use a screwdriver to remove the screws. Lift the shroud from the compressor to reveal the upper and lower pressure limiter adjustment screws. The screw closest to you is the lower, the one farthest away is the upper.
Turn the compressor on and allow it to charge. Make a note of the pressure on the pressure gauge when the compressor turns off. Pull the air release valve to release pressure from the tank. Look for a metal and plastic valve near the air outlet with a metal pull ring through it. Watch the pressure gauge and make a note of the point at which the compressor turns back on.
Consult the tool manual or tool manufacturer's website for the tool you use most often. Look for the optimum pressure range. You may also find this on a printed label on the tool itself. It should indicate the best pressure for operating the tool, for example, "Works best @ 60-120 psi." Psi, which stands for pounds per square inch, is the same measurement you wrote down from the pressure gauge.
Adjust the lower limiter control screw by turning it clockwise to increase the pressure, or counterclockwise to decrease it. Adjust the upper limiter control screw in the same way. Recharge the compressor, noting when it kicks off. Release pressure and note when it kicks on. Adjust the screws as needed until the compressor consistently maintains optimum pressure.
Replace the shroud on the compressor. Replace the shroud screws and tighten them with a screwdriver.