An air compressor is the workhorse of many workshops, driving tools as diverse as nail guns and sanders. In busy shops, the compressor works almost nonstop. Setting the pressure on the compressor to the correct setting will allow you to get the most usable time between cycles for the tools you most commonly use. To do this you will need to locate the pressure limiter adjustment screws. Most compressors have two--one for the lower limit, or kick-on pressure, and one for the upper, or kick-off pressure.
Locate the limiter cover, which is typically a plastic cover located on the top of the compressor, near the outlet. Remove the screws holding this cover in place with a screwdriver and lift it off to reveal the limiter adjustment screws. These two screws typically have plus and minus signs to either side.
Start the compressor and watch the air gauge. When the compressor kicks off, make a note of the pressure. This is the upper limit. Locate and pull the pressure bleed valve. This is a plastic and metal valve with a pull ring. Pull this valve out to release the pressure. Air will rush out through this valve. Release pressure until the compressor kicks back on, and make a note of the reading on the pressure gauge when that happens. This is the lower limit.
Adjust the limits up by twisting the screws clockwise. Adjust it down by turning them counterclockwise. Consult your manual to determine which screw is which, or turn one screw as far clockwise as possible and rerun the test cycle, noting which limit is changed.
Adjust the pressure limits as required by your tools. Standard pressures are typically printed on the safety label of air tools. Adjust the upper and lower limits as you like until the compressor works as smoothly as possible. Reset the cover and tighten the screws to conceal the adjustment screws.