laboring compressor start

[894183]

I have a Porter Cable C3151 oilfree compressor.
I just installed a new pressure switch, piston ring kit, and valve plate assembly.
When the tank is empty and has no pressure built up, the compressor starts and runs like new. When there is pressure in the tank and it is time to cycle, the compressor labors to start. Sometimes it finally will run, but most of the time it throws a 25 amp breaker, then I have to drain the tank to get it to start. Is there another part or kit I should install?
Would the D30144 start/run capacitor kit do the trick?
or is there something else I need to do?
any help appreciated, running to the breaker box every cycle is getting old!!!
thanks

[Tinkerdave]

Hi, Yes your capacitor is most likely the problem.The only other thing that could make it do that would be if the unloader valve was not working right. once the compressor pumps up and shuts off you should hear a short hiss as it dumps the pressure of the head.Hope that helps.Good luck.
Tinker

[UtahAV]

This could also be an issue with the check valve that is between the tank and the cylinder. When the check valve fails it allows the pressurized air from the tank to bleed back to the cylinder. The motor usually can't overcome this pressure when it turns back on.

Good luck,

-UtahAV
-Mark

[dan1]

thanks guys
I don't see a check valve, if there is one it must be part of the valve plate, which is new.
The unloader valve is in the pressure switch, again it's new.
I replaced the start capacitor even tho' it tested ok...no change in performance.
could there be a problem with the motor?
I bought this in '07...
It does start and run fine some of the time, but does labor regularly.

[UtahAV]

What is the type number of your compressor? (located on the same tag as the model number) The check valve for the type zero appears to be discontinued. The Check valve for the Type #1 and #2 is part #A19996. On the parts diagrams for all of the types the check valve is item #13. I really think that it is the problem. I just hope that your machine is not the type zero.

I hope this helps,

-UtahAV
-Mark

[dan1]

Mark-
thanks so much. I was thinking I would have to replace the motor.
this part seems to be almost hidden to any one not knowing it's there.
I'll order this today and hope it fixes the problem.
I thought too, that the pressure wasn't releasing, but thought the check valve was part of the pressure switch...
thanks again
~Dan

[dan1]

I went down to the shop and took the check valve out.
To my surprise, there was a small chip of stainless steel (from the old valve plate) stuck in it.
I removed the chip, sprayed it with a light lubricant and put it back in the compressor.
The compressor cycled 20 times with no problems....
glad to have the internet, and especially please to have this forum...