Air compressor problem

SOURCE: air compressor 3 gallon

When I turn compressor on it does not build up any pressure ?

Joe Garcia

• 210 Answers
• Posted on Mar 23, 2009

SOURCE: Mastercraft 2.0 hp air compressor will not build up over 25 psi

sounds like a bad or broken valves in the head. crankcase needs a vent which is sometimes a small hole drilled into the oil fill plug and will normally blow some air out the vent while it runs

SOURCE: The compressor relief valve keeps popping, compressor runs

What pressure is it popping off at? You might have to adjust the pressure switch to a lower setting.

SOURCE: craftsman compressor will not come up to pressure

Don"t worry, even the best techs overlook a thing or two during repairs. Lets go over some basics to determine where fault is located. You will need to do some simple tests. If there are leaks the compressor may not reach set pressure. I use soapy water on all connections and on the head/headvalve while compressor is running. Make repairs as necessary. If still low pressure, while compressor is running and has reached max obtainable pressure (still low 70 - 80 lbs), carefully place finger over intake port hole (remove filter). If the compressor is pumping normally but leaking there will be ample suction at intake and cause the compressor to speed-up when intake is obstructed with finger. If you feel plenty of suction and no visible (soapy water) leaks, then the problem is probably the cylinder /ring is not correctly seating and air is leaking past cylinder. Make sure that the cylinder /piston ring is properly alighed and that the lip on the vinyl ring is up toward the head. If you do not feel suction but rather air seeming blowing out of the intake, then the problem is the headvalve plate/reed valves are leaking. The reeds must seal perfectly on their seats and not bent or have obstruction. Replace as necessary. Only one other thing to check and that is the intank check valve. Easy to check. Run compressor till you have about 70 lbs in the tank then unplug compressor. Carefully loosen the inlet hose at checkvalve and listen for air leaking out of tank. If leaking replace checkvalve. Use caution when removing head to try and save the gaskets. Good luck on your repair and email if you have other question.

SOURCE: Dewalt 4 gal air compressor will not build pressure in take.

The bleed valve is an unloader of sorts that allows the compressor to start with-out a load. It closes when the pressure in the airline reaches about 20-25lbs with good volume. If air volume is not sufficient, the valve will not close. To solve the problem lets do a few tests. A long cord will reduce power and reduce air volume. Try powering the compressor with-out extension cord. If bleed valve closes when you do not use a cord, the compressor is not getting enough voltage, use shorter cord of the 12 gauge quality and more hose to reach work. If valve still does not close, check for air leaks on all fittings including around pressure switch and drain valve with soapy water. Repair as necessary and retest. If no leaks were found, temporarily plug bleed valve port with screw/bolt and run compressor till set pressure cut-off while counting minuites/seconds. The compressor should fill and shut off within three minutes or so. If it takes an unusually long time to fill, then the reed valves /valve plate is worn and leaking pressure back into cylinger. Leaking valves will usually result in very hot discharge airline/air. Reinstall the bleed valve after test. Parts and partslist are available at www.toolpartsdirect.com . Good luck on the repair and email if you have other questions.