Air compressor is exceeding it's maximum PSI rating

by Shaun R.
(Fairmont, WV, US)

Hi, I have a Kobalt 30 gallon air compressor that is rated for a max pressure of 155psi. Everytime I've used it, I simply tighten the screw on the bottom, plug it in and turn it on. It automatically fills to 155 then cuts off.

The last time I plugged in the compressor I followed the same motions and I happened to look over and see that the pressure had built around 165psi.

I immediately shut it off and bled the excess pressure from the tank.

My question is, what is causing it to surpass it's previous limit, and can I adjust it back down? The compressor is only about 4 months old and I've only filled and drained the tank about 10 times. The only control I don't know about is a black knob on the back, but I'm scared to mess with it unless I know what it does. Thanks in advance.

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Bill says...

Hi Shaun.

Have a read of this page about pressure switches.

It's the pressure switch that turns the compressor on and off, and if the cut out pressure switch fails, your compressor will keep on running.

You need to get that fixed right away. Is it under warranty? Ask the store where they send their units to get fixed under warranty, and get it there.

Cheers,

Bill