YACQ (Yet Another Compressor Question)

Well, looking over my compressor, trying to get it ready for when my VFD arrives, there seems to be a few things not show or show differently in the documentation I got from Quincy.

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Pictures 1 and 2 are not shown in my manuals at all, so I'm assuming this is an end-user setup, and may not be standard. Picture 3 is what I'm assuming is the pressure switch, though I haven't opened the case yet to be sure. The two wires from it are the two coming in from the lower left in picture 2. If I'm understanding this right, if I detach these wires, the motor will run continuously, and when pressure is reached, the unloader towers in photos 5 and 6 kick in to keep it from compressing.

If I want it to stop and start, I need to hook up those two wires to the VFD's sensors and let it control the motor that way, correct?

Also, I'm not sure what the section is in picture 4, other than the air coming from the head goes through it before it goes into the reciver tank.

Also, the flywheel turns smoothly by hand and you can hear the cylinders compressing.

I was also wondering, they recommend changing the oil first thing, but I was also considering changing all the gaskets too. Is that overkill, and just a chance for me to mess it up?

Another thing I was wondering about, all the drawing in the parts manual for the plate on the side of the crankcase show only one dipstick, but mine has the dipstick and a plug nut.

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Any idea what it might be for?

Thanks again for the help everybody...this is my first big compressor.


Reply to
Todd Rich
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Yes, this definitely appears to be a pressure switch.

The two wires from it are the two coming in from the lower left

I don't think so. Photo 5 shows the oil pressure pickoff that controlls the unloader. I believe the unloaders switch off when the compressor develops oil pressure, and are not controlled by air pressure at all.


It may be a check valve.

Filling the crankcase?


Reply to
Jon Elson

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