Craftsman 3 Gal compressor not building more than 25 psi
by Bob Hall
(Browns Mills, NJ)
i have read your posts and and tore down my compressor. both reed valves are fine, gaskets look new, piston rings look fine to me, checked the littel white valve that is in the copper tube that goes to the switch ....what else should i check...it runs but holds at 25 psi...note that due to not draining the air after use, i found alot of dirty water in the tank when i removed the drain valve...could this have caused any damage to the unit? what else should i check and how would i check it?
Bob, good effort in trying to figure out what's going on with your Craftsman compressor, and for the complete post. It helps me try to help you.
You say the air compressor holds at 25 PSI. I take that to mean that the compressor keeps running, and the pressure never goes past the 25 PSI, or does the compressor stop at 25PSI?
If the latter, it's the pressure switch, I think.
If the pressure builds to 25 PSI and stays there with the compressor still running, and the motor doesn't seem to overheat (indicating overload) then you have a pressure related leak I suspect, and even though the valves and the gaskets look good on visual inspection, I think that under pressure one or both of these items are leaking.
Use a lighted match at the intake port to see if any air is huffing out while the compressor is running.
If not, then I'm going with a pressure related gasket failure.