CFM means cubic feet per minute. Very often the actual operating range of an air compressor is not indicated correctly by the manufacturer. Because of this, the only way to determine the actual CFM of your best air compressor for home garage is to test it yourself. Then only you will be able to increase the CFM on your air compressor. But, before that let us see how we can measure the actual CFM.
Step 1 – understand the capacity of the tank of the compressor in gallons.
Step 2 – Divide the volume of the tank by 7.48 (7.48 is the number of gallons in a cubic foot).
Step 3 – Free the air from your compressor.
Step 4 – Start filling your compressor tank with air. Record the amount of time it took for the tank to refill while paying attention to your tank gauge.
Step 5 – Record the PSIG value indicated on the tank gauge when the compressor starts and lend it to the value obtained when the compressor has finished.
Step 6 – Divide the difference between the two registered psig values by 14.7.
Step 7 – Convert this number to minutes. Multiply the result by 60 and you will have obtained the CFM from your compressor.
How to increase the CFM?
There are three factors that affect air compressor efficiency and performance. First, the compressor must have the ability to create pressure. Second, the capacity of the tank needs to be maximized. Third, the air flow out of the reservoir has to be maintained at a constant level. The air capacity of the compressor is one of the important characteristics. The CFM (Cubic Feet Minute) is the unit in which you must look to know the air capacity of the machine. Follow these instructions to increase the CFM.
Plug in the compressor and turn it on again. Let the pressure build up until the compressor starts. Spray soapy water around the fasteners in the compressor and looking for bubbles. Use a wrench to tighten the accessories with the bubbles escaping around them until the bubbles stop forming. Locate the purge valve at the bottom of the tank. The purge valve is a small, round, spline nut in the lower part of the tank belly. Take the nut with locking pliers and turn left to open the valve. Let the air out of the tank, pushing the condensed water in the tank out with it until the air that comes out is dry.
Remove the screws from the plastic cover on the top of the compressor with a screwdriver, and take it off to reveal the two adjustment screws below. The furthest screw is the upper limiter, controls the high pressure. The closest is the lower limiter which controls the way under pressure.
Check the label just above the air connection of the tool that uses most of the optimal operating range. This is expressed as two numbers separated by the word “a” followed by psi, which means pounds per square inch. Pull the air exhaust valve. Look for a plastic and metal valve near the outlet, and pull out on the ring to release the air. Keep an eye on the pressure valve, and make a note of the pressure when the tank starts at.
Allow the tank to pressurize, and make a note of the pressure when the compressor turns off. Turn the adjusting screw clockwise upper limit to lower the upper pressure and to the left to raise it. Do the same with the lower limit adjustment screw to raise or lower the lower limit. Tighten the screws, and load and relieve the tank pressure until the pressure readings are aligned with the tool’s operating range.