Alltrade air compressor will not restart unless the tank is almost empty.

This is an Alltrade air compressor purchased from what was then Grand Auto, and it acts like the numerous postings here.

Typically, when the compressor drops about 15-20psi, it tries to restart, but it either trips the house circuit, or it trips an internal overload switch witch resets after some amount of time.

I have checked the Unload valve, and it seems to work as per your descriptions.

THE DIFFERENCE in my scenario, is that if I empty the tank with the power off then restart and refill the tank (it will start easily when the tank is almost empty) a half dozen times or so, then it will work just fine...consume about 15-20psi of pressure, it automatically restarts, and fills to cut off levels.

Problem is, that unless I am consuming a lot of air pressure in relatively short bursts, the motor seems to "cool down," and doesn't restart as it should.

It is plugged directly into the wall in a 110V, 10amp circuit. It had this problem from when it was new; I bought it, and did not use it until after any warranty had expired. it is not used much...fill the car tires periodically.

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Bill says...

Please dump the air, restart, and then monitor the unloader valve to be sure it actually unloads the compressor. I know you say "I have checked the Unload valve, and it seems to work as per your descriptions." but just double check, K?

Thank you for providing the info you did.

If the unloader valve is working correctly every time, then I am going to suggest that your start capacitor needs to be checked. You can find info on that from the site map page.

Cheers,

Bill




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Alltrade air compressor will not restart unless the tank is almost empty.

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Jan 11, 2012
 Increased amps makes it work
by: Russ

Bill;
I had the capacitor checked out professionally, and it is okay. Found that if I plugged the unit into the washing machine plug, it works just fine...starts and restarts normally. That plug is a dedicated 110V/20amp circuit. My conclusion is that I need to somehow get a little more juice to the motor for the restart cycles. Do you think putting in a larger start capacitor would help?
Russ

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It were me, I would take a feed off the washing machine supply line for the compressor, and make sure I didn't run both at the same time.
Jan 01, 2012
 Checked Start Capacitor
by: Russ

First, Happy New Year.

I followed the directions to test the start capacitor. What I found is that when I "charge" the capacitor with my meter, it does not hold the charge. It spikes initially, then drains in about 3 seconds. This happens consistently, and also when I reverse the polarity as described in the test instructions.

I charge it (with he meter) and then before it discharges, I touch the meter leads to one of the terminals and the metal body of the capacitor...no readings from either terminal. I am led to believe that all of this means I have a bad capacitor, (yet it works on very low to no pressure?)

Please confirm that based on what I have said the capacitor is bad. I am not an "electrical kinda guy." Also, what type of business/"store" should I look for to find a replacement.

Thanks...Russ

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Russ, I am not electrical either. I'm a compressor flow and user guy. Yet, the run capacitor needs to add its supply to the power source for the motor, so that the motor can handle the increasing load. If the capacitor is bad, the compressor will likely run with no load (empty) but stall out and blow fuses or not run at all with load (pumping against air pressure in the tank). Sounds like your capacitor to me.
Dec 22, 2011
 Alltrade-check start capacitor
by: Russ

I have not been able to find info on checking the start compressor. It is probably my lack of expertise in navigating your site map. Are there instructions as to what I need to do? Tried looking under all of the categories. Under which category should I look?
Thanks again,
Russ

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Site map page, under electrical issues, capacitor checking.
Dec 20, 2011
 Double checking Unloader Valve
by: Russ

Per your request, I filled tank, and when it hit the full cut off pressure, motor stopped and I could hear the psssst. Did this numerous times, and it consistently works this way.
Thanks, Russ

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Thank you for checking. Now, are you up to checking the capacitor?

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