Replacing the air pressure switch

by Bruce E Schmidt
(Davidson, NC)

We have to replace the air pressure switch on a single stage Farmhand air compressor 60 gal.

The pressure switch has 4 connections on it with plastic hoses and fittings that I haven't came across before, looks like you have to push on the fittings some how and helped would be appreciated.

Bruce
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Bill answers...

Hello there Bruce.

Is the question how to use an "instant fitting"?

If so, here's a "heads up".

An "instant fitting" is a remarkable device for quickly installing and removing air line.

It works this way.

Inside the tube port of the fitting (usually there is one side threaded, and the other side has a hole into which you push the tube) is a metal (usually stainless steel) collet that compresses out of the way as the tube is slid in and by it.

There's also an "O" ring through which the tube slides to pass through the collet.

The collet has "fingers" that point into the fitting.

As the tube passes by them, they are depressed (no not sad, just pushed out of the way) by the tube.

When you try to pull the tube back out, the collet fingers actually pierce the surface of the tube a little, preventing easy removal of the tube.

When there's air pressure in the tube, it expands somewhat. That makes the tube bigger, and makes the fingers on the collet "grab" the tube even harder, making it almost impossible for the tube to leave the fitting while it's under pressure.

There will be a slide ring or pressure ring on the outside of the fitting near where the tube is inserted.

By pushing this ring towards the fitting you will depress further the fingers on the collet, allowing them to move away from the surface of the tube, and theoretically allowing the tube to be removed from the fitting.

No, don't do this while the tube is under pressure.

Yes, void the pressure from the tube before trying to remove it.

Will removing it be simple? Nope. Over time, the fingers on the collet will stick into the tube, and even aggressively pushing on the slide ring may not dislodge the fingers.

After a while, you may curse the whole concept of "instant fittings", yet some are better than others, and actually work, even if installed on a charged air tube for some time.

If you go to this page, look at the blue ring on the in-port of the fitting. That's the slide or tubing release ring.

Does this help, or have I answered the wrong question?

Cheers,

Bill