An air compressor is just like any other device. It needs maintenance from time to time that ensures it is working properly. One of the more important tips is to drain the moisture from the compressor tank. This is because when air is pumped into the tank, it also brings in the moisture content of the air. No matter the size of the unit, you will need to drain away the moisture lest it becomes problematic for the operation of your air compressor.
Draining an Air Compressor – Steps
To properly drain an air compressor, here are the steps to follow.
1. Turn Off the Compressor
start by making sure that it is turned off. Place the switch in the off position and unplug the unit if you want to ensure that it is completely off.
2. Release the Pressure
You need to reduce the pressure inside the tank to below 10 PSI. You can do this by pulling the ring located on the ASME safety valve. Before pulling the ring, be sure that you are wearing safety glasses as dust or debris might be stirred up by the air that is being released. Keep pulling on the ring until the PSI gets 10 or the tank is empty.
3. Release the Drain Valve
Now you can release the moisture buildup from inside the tank. Locate the drain valve on the tank which is normally on the bottom of the tank. Once you find the drain valve, open it and let the moisture flow out. You may have to tilt the tank back and forth to ensure that all the moisture inside is removed.
4. Close the Drain Value
Once you have released all the moisture, close the drain valve. Make sure it is shut tight. If you are going to use the air compressor right away, you can turn it back on so the tank will pressurize. Otherwise, you can pressurize it on the day that you will use it again.
Here is a video that explains the steps.
How Often Should You Drain?
Ideally, you should drain it after every use. If you have used the air compressor that day, be sure to drain it before you leave that night.
But a more practical approach is to drain the air compressor once a week. For example, an air compressor for nail guns or impact wrench doesn’t work continuously and is considered as light use. However, in case of heavy use such as spray painting, draining at the end of a day of work will keep your compressor running for long.
What Happens when the Air Compressor is Not Drained?
By not draining the tank, you risk rust building up on the inside which will weaken the metal. At some point, the rust will compromise the integrity of the tank and when pressurized will explode. The tank will not go off like a bomb, but rather explode outward at the weakest point.
The intense noise may damage your ears, but more importantly the sudden outrush of air may contain small metal particles from the tank that fly across the room. Such particles may cause anything from a small irritating scratch to something far more serious depending on the location of where they strike.
To avoid all this, be sure to drain the tank at the end of each day when it is in use. By removing the moisture, it will stop rust from forming inside and protect the tank which protects you and everyone around it.
Dan Miller is a professional toolmaker with extensive experience in the metalworking and tooling industry.
An avid DIY enthusiast and passionate hobbyist woodworker, Dan shares his expert knowledge here.