How Do You Know If The Pressure Switch Is Bad On An Air Compressor?

Author: E. Silva (aka Mr. Awesome - The Niche Specialty Expert)

Well, if you got a used air – compressor off of craigslist or something like that, you might have a ton of issues like a bad pressure – switch and anything else that the prior owner did not want to disclose, to begin with …. which is why I buy new, always. I do not buy used or re – furbished air – compressors, though I do get other kinds of products used, if there’s a good deal going on. But when it comes to this more – sensitive type of a product, I prefer to go with better make, condition and quality, at the end of the day, even if it means that I have to spend a bit more to get a better product. Those are just my thoughts —- take them or leave them, please …. but I do suggest you hear me out on that, as it can save you a whole lot of heart – ache to just buy a new air – compressor …..

Now, then, when the pressure – switch on a NEW ( OR AT LEAST SEMI – NEW OR RECENTLY – NEW, he heh e heh eh eh heh ) air – compressor is bad, you are looking at something else entirely. Let me dive into this further for just a second. Can I? With your permission, let me share some more I’ve found …

I would like to bring this fact to your attention next —- the very plain fact that, if you have another air source, as well as an ohmmeter, handy, then you can test this all out for yourself … plain and easy to do, it is, as a matter of fact. Unplug the compressor from the wall connection ; unscrew and remove the main unit’s housing. Disconnect all wires connecting the terminal block and the pressure – switch itself ( very important step, as you might imagine, he he he he heh ehh ) . If you are not quite sure what these wires look like, they are either blue or brown, most of the time ( and you can “google image” them or look them up on YouTube tutorials as well, for free, of course … thank God for the internet ) . Your black – white wires have to remain connected, though ; keep that in mind here. This is of equal importance to note.

Now, then, find the valve. Send air to your switch. Place your ohmmeter’s leads on the loose wires accordingly. If the ohmmeter reads “0” after a few secs, then that means the pressure’s keeping the switch closed ( as it should be ) , and thus, the pressure – switch still works and is doing its job. It’s not bad. But if it reads “infinity”, “OL”, “open” or something similar, then the pressure – switch is bad. In that case, you’d need to repair … maybe just replace …. it.