Question about Coleman 3HP 11 Gallon Oil Lube, Direct Drive Horizontal Air Compressor

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Trips breaker starting under load

Runs from empty to full, when pressure drops to start pressure breaker trips

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The problem that you describe is caused by pressure in the airline due to faulty in-tank check valve and/ or the unloader at the pressure switch. When the compressor cycles off the pressure switch releases the air that remains in the air line thru a small valve. There is a 1/4 " tube extending from the check valve to the switch. Listen for the release of air as soon as the compressor stops. There is a small metal tab that pushes on the unloader valve that may need to be adjusted. The motor does not have enough power to start pumping if there is air/backpressure in the air line. If these parts are working correctly then check the value of the start capacitor and use meter to measure. The cap should test within 95 % of stated value. Replace parts as needed. Enjoy

Posted on Dec 21, 2008

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