# Pump will not turn under pressure



## Jsucci (Jan 7, 2018)

I have a 60 gallon porter cable stand up compressed that runs fine if the air line going from the pump to the tank is unhooked. Once the line is put back on it'll run real slow and stop moving. It almost looks like the pulley for the pump might be wobbling some. I tore the pump totally apart and everything moves free until I get the air line going to the tank back on. I have some air in the tank so i tries pushing the check valve and it works how it should. Could it be a bent shaft on the Pump? Thank you.


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## motormonkey (Jul 10, 2016)

> ...compressor runs fine if the air line going from the pump to the tank is unhooked. Once the line is put back on it'll run real slow and stop moving.


I'm guessing that the compressor starts and runs for a few seconds, and then slows down and stops as pressure in the outlet line builds. If the motor is working properly, I would expect it to draw an abnormal amount of current if it got stalled like that... enough to dim lights or pop a circuit breaker. You didn't say anything about it popping a breaker or showing any signs of abnormal current. I suspect something is wrong with the motor. If it has a run capacitor, that could be the problem.


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## Jsucci (Jan 7, 2018)

It does exactly what you are saying but doesn't pop the breaker or dim the lights. I swapped out the motor yesterday and it does the same thing.


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## motormonkey (Jul 10, 2016)

Maybe something is blocking the line from the compressor to the tank? Hook the line up, release all the pressure from the tank, run it, and report back.


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## Jsucci (Jan 7, 2018)

I did that yesterday. The line is clean. I tried pushing the check valve open with a screw driver and it opens and closes like it should


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## motormonkey (Jul 10, 2016)

The compressor slows and stops immediately when the line from the compressor to the tank is hooked up, even when there is no pressure in the tank???


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## Jsucci (Jan 7, 2018)

Yea. I can unhook the line and it runs fine


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## motormonkey (Jul 10, 2016)

Your descriptions and answers are not logical.

You say that the compressor slows and stops immediately when the line from the compressor to the tank is hooked up, even when there is no pressure in the tank. You also say that there are no restrictions in that line. That simply cannot be.

Sorry. I guess I can't help you.


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## Jsucci (Jan 7, 2018)

I ran a piece of wire thru the line and there were no restrictions. I pushed the check valve open with a screw driver and it opened and closed like it should. Is it possible that the pump is not building enough pressure to open the check valve and the pressure is just building up in the line? I have seen this happen at work with steam. There hasn't been enough steam pressure to push the check valve open when there is water on the other side of it


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## motormonkey (Jul 10, 2016)

Stopping a compressor and motor of that power rating should expend quite a bit of energy. That should manifest itself as high pressure, noticeable heat, or excessive current... somewhere. If not, again, the motor is suspect.


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## Jsucci (Jan 7, 2018)

Even with a brand new motor it does the same thing?


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