Air compressor pressure switch

by Dan
(Pontiac, MI)

On most upright air compressors I have seen there is a small air line (either 1/4" metal or dot plastic tube) running from the side of the tank to to the pressure switch on the outside of the tank. I have a friend who's pressure switch was leaking where this dot tube connects into the presure switch. He completely disconnected the connector from the pressure switch and there appears to be some type of little valve or shut-off switch on the inside of this connection. He had his compressor running (shutting on and off) without this line or connection/switch connected.

What is this line and connection/swicth at the end of the small line for? What does this do in regard to the funtion of the compressor and pressure switch? Can you run the compressor without this with-out any danger to people or the air compressor?

Thank you - Dan

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Bill says...

Hello Dan. What I think you are describing is the unload tube running to the unloader valve.

The unloader valve is near or attached to, and is operated by, the pressure switch.

Go to the Valve page, and click the link to both the Unloader Valve and Check Valve for more info, and how these two important valves work together.

Cheers,

Bill