10HP Quincy QR-25 compressor unloads when hot in hot weather

We had to use our 10HP QR-25 Quincy compressor a lot today and it is
95 degrees or so. When it gets hot, for some reason it unloads and
runs, but does not pump air. After it cools down, it starts and seems
to pump just fine. Then after a while it unloads and no longer runs.
The only things that I could suspect would be rubber membranes that
push on the unloaders, any other idea?
thanks
Reply to
Ignoramus29430
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Maybe the hydraulic unloader control on the side of the block? The membranes usually fail by tearing & you would hear an air leak.
MikeB
Reply to
BQ340
I am thinking, perhaps the lubricating oil becomes very hot, less viscous, and oil pressure drops, and the hydraulic oil pressure "safety circuit" causes unloading?
i
Reply to
Ignoramus29430
Newp. Perhaps find a way to run cooler air over the fins via a mister or water-cooled heads. Just machine some up, Ig. Piece of cake. ;)
Reply to
Larry Jaques
Yes. I could see that happening if the o-rings are hard & leak a little.
Also maybe check the oil filter screen, the big hex plug in the bottom of the sump.
I was impressed with the Quin-cip oil, it would not turn black & much less carbon formed on the valves compared to all the other oils I tried.
MikeB
Reply to
BQ340
We have a big pedestal fan to help cool and use synthetic compressor oil. Do check the unloader membrane and hydraulic air valve.
Reply to
Tom Gardner
If this compressor head has an oil pressure system, adding an oil cooler is a trivial thing - They make little cooler cores for power steering on cars and light trucks, or get the smallest automatic transmission size. A few rubber mounts to attach it to the belt cage, attach in line.
Then get the soundproofed closet you have the compressor in some outside air ventilation. Might have to mount a roof jack and a power vent, and then cut a few intakes in the wall behind it.
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Reply to
Bruce L. Bergman (munged human readable)

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