It’s a Porter Cable cpfc2tv3525vp 25gal compressor.
by Eric
(Naples Fl)
My compressor has developed an issue..at first I thought I had a problem with the pressure switch but after snooping around here I realize it may be I believe the unloader valve.
Here’s what it does.
It comes on fine, goes all the way up to pressure, motor clicks off and the unloader valve opens up. Only problem is it never closes so it bleeds all the way off until the point that the motor kicks back on and we start the whole cycle off again.

I should also mention that NEAR that point of where it is getting ready to come on the motor struggles but does not quite turn hums a little at this point if I don’t hit the lever to turn it off it will trip the breaker.
In order to start it at this point I have to bleed off additional air and then I can throw the switch and start this cycle off again.
I should mention that although this compressor is not directly in the weather it is outside and it is very humid here in Naples fl all the time which brings me to my next issue.
My drain in the bottom of the tank has begun to leak, I have tried Teflon tape and it is not as bad but it is still there. Any thoughts you all might have would be greatly appreciated
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Eric, lets tackle the little problems first.
If your unloader valve is bleeding air when the air compressor stops and the leaking continues after a second or so, then check out your CHECK VALVE for I think it is leaking. See the check valve page for more info on it.
Or, if it bleeding air all the time, it may be that the unloader valve isn’t working at all, and the leak is from the tank, not over the piston, which might account for the hard startup.
If the drain is leaking, replace the drain. If it is, as I suspect, a leak due to corrosion, it may be time to look at a whole new compressor.
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