Bostitch compressor has air leaking so bad it won't build over 20 lbs.

by Eddie
(Lake Charles, LA)

I have a bostitch cap60 compressor that is leaking air so bad it won't build over 20 lbs.


the leak is somewhere by where the rislan tube connects between the electrical cord. I suspected a crack on the pressure switch assembly, so I bought a whole new assembly.

After replacing complete assembly, I still have the same issue.i feel the air leak between the rislan tube and the cord. Any suggestions.
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Eddie, try this.

Unplug the compressor, dump all of the air from the tank through the tank drain valve, find where the line from the pump head enters the tank, disassemble the line from the tank check valve there, and inspect / clean / test the tank check valve.

Reinstall. Start the compressor.

Any change?

Bill

Comments for Bostitch compressor has air leaking so bad it won't build over 20 lbs.

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Nov 04, 2013
Bostitch compressor
by: Eddie

Bill, I did check the nonreturn valve and it was appeared to be working. However while the compressor is running I am getting air out of the end of the rilsan tube where it ties into the pressure switch area. As soon as I turn off the compressor, the air stopped leaking from the rilsan tube. I disconnected the rilsan tube and plug it off to see if the compressor would build pressure. However, the compressor would never build over 30 pounds of pressure. Then when I turn the compressor off, there were no out air leaks with tube plugged off. I've come to the conclusion that this Bostitch air compressor is a piece of junk. This is a shame since I very seldom used this compressor. Thanks for the help.
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Eddie, if you have disconnected the unloader tube that runs from the tank to the pressure switch, then, as the compressor runs, it is normal for air to flow out of that tube. That outflow should have stopped if the tube had been connected to the pressure switch as when the compressor is running the unloader valve is non-passing, and that's what keeps the air in the tank.

When the compressor stops at cut out, the unloader valve opens to dump air over the piston and at that point, it is the tank check valve that keeps the air in the tank.

This "I am getting air out of the end of the rilsan tube where it ties into the pressure switch area" is symptomatic of a fitting leak, nothing else.

This makes sense " As soon as I turn off the compressor, the air stopped leaking from the rilsan tube." because the air is being held in the tank by the tank check valve.

B.



Nov 01, 2013
Air leak
by: Eddie

Bill, I pulled apart what is called the non return valve on the parts diagram and cleaned. Put back together and ran. While running, there is still air coming out as described. When I turn it off, it's not leaking. I disconnected the rislan tube and ran. The air is coming out from where the rislan tube connects to the check valve. When I hold my finger over the brass connection where the tube connects, the tank will build pressure. After shutting off, I can remove finger from brass fitting and it stops leaking air and the tank holds pressure(20lbs). Is this indication that the check valve is bad. Before it still leaked after shutting down compressor. Also, what is the purpose of the rislan tube?
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Eddie, not having a photo of your compressor in front of me, I can only surmise that the tube runs from the non-return valve (check valve) over to the pressure switch and into the unloader valve.

It does sound to me as though your check valve is pooched.

After you cleaned it, did you test it? You can sometimes do that by blowing into each port and determining which way the air will not flow, and that's the port that sits down into the tank to stop air from flowing back out of the tank.

Bill


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