Air compressors are generally equipped with a pressure switch that allows you to better control and gauge the level of pressure at which the unit is operating. However, when the switch is leaking, this isn't always the case. A leaking switch can cause the gauge to provide inaccurate pressure reading and cause the compressor to work at a less than efficient level. Getting to the bottom of the leak can help resolve the problem.

Tank Check Valve Failure

A problem with the tank check valve can cause air to leak from the pressure switch. To determine if this is the problem, you first need to find out where the unloader valve is on the compressor. Once located, power off the air compressor and let it rest for a few moments. Next, pass your hand around the unloader valve to see if you can feel any air on your hands.

If you can feel air, the tank check valve has likely already failed or is misplaced. In the event of a failure, you will need to have the tank check valve removed and replaced with a new unit. If it's simply misplaced, you should be able to refer to the owner's manual to assist you with repositioning the valve in the correct position.   

Worn Diaphragm

On the inside of the pressure switch is a diaphragm, which basically works as an added aide in gauging the pressure level of the compressor.  Particularly if you use the compressor on a frequent basis, it's not uncommon for the diaphragm to start showing signs of wear, including cracking, over time. Once this structure has a hole in it, as air starts to pass from within the tank, it will also seep out of any cracks within the diaphragm.

In addition to frequent use, if there is an excessive amount of pressure within the tank, this can put pressure on the diaphragm and cause it to crack prematurely. Unfortunately, once a diaphragm has reached this level of wear, the only solution is to replace it. Once you've performed this step the problem should be resolved.

A leak from the pressure switch doesn't have to signal the end of your air compressor, but it is definitely something that requires your attention. Once you have determined the source of the leak, make sure you're making any necessary repairs or replacements to return your unit back to a more efficiently operating state. Click for more info.