Whether you are an at-home hobbyist or a professional construction contractor, you probably know the value of a good air compressor. Air compressors can be used for cleaning dust and debris, airing up tires, painting, or using pneumatic tools that perform many different jobs. However, not everyone knows how to care for their compressor as they should.
How long can you leave a compressor running? Depending on the size and type of compressor, air compressors can be left running anywhere from a few hours to 24 hours a day, seven days a week.
Knowing your compressor and its needs and limitations is vital in keeping this invaluable equipment operating correctly.
Types of Air Compressors
There are two primary types of air compressors used in the home or on construction sites. These compressors fall under the category of Positive Displacement Compressors. This means that the compressor stores outside air in its cavity and compresses it to create air pressure.
Dynamic or Centrifugal Compressors also exist, but they used in chemical plants or large manufacturers. Their design and size are vastly different, which enables them to run in ways standard compressors do not.
Reciprocating Compressors
Reciprocating air compressors range in size and power. Small 1-gallon air compressors often have a ½ horsepower motor that can reach a maximum of 100 PSI. However, reciprocating compressors can be as large as 30 horsepower and reach over 100 gallons.
A reciprocating compressor is the type of compressor you typically find on smaller construction sites, small shops, or in someone’s garage. These compressors operate similarly to your car, as they have at least one piston inside of a cylinder that compresses or displaces the air inside to create pressure. Reciprocating compressors are offered in single-stage or multi-stage motors that determine the pressures they can reach.
Because of this design, these compressors have many moving parts that generally need to be lubricated with oil. These moving parts create friction, and with it, heat. Furthermore, the more parts move, the more wear you will begin to experience.
Because of the heat and wear, reciprocating compressors cannot be run constantly. They require time to cool down. This aspect is known as a “Duty Cycle’ of the equipment, and that information can be found in the manual. It’s important to know what sort of work you will be doing with your compressor, so you know what duty cycle to look for.
Rotary Screw Compressors
Rotary screw compressors are the other common air compressor type, but these are generally larger, more industrial-sized pieces of equipment. They are often found in large shops or construction sites that have a higher demand for constant air pressure. Designed for continuous use, these compressors can run 24 hours a day, seven days a week, with much less fear of failures or mechanical issues.
This type of compressor uses spinning rotors instead of pistons. The rotors turn in opposite directions,
trapping pockets of air between them and forcing it into the chamber.
Some rotary screw compressors do require oil, but others do not. Their lower friction design means less heat gets produced, which also goes a long way in eliminating wear and tear on the mechanical components.
You Can, but Should You?
Tools are expensive, and compressors are certainly no exception. But the only thing worse than a tool needing to be replaced is a tool needing to be replaced while in the middle of a project or job. Lost tools, money, and time is a terrible combination.
With that in mind, it should not come as a shock that manufacturers and professionals suggest shutting off machinery when not in use. However, many people still suggest that there’s no problem leaving your compressor running overnight, or even for days at a time, when not in use. Let’s look at some reasons why this may not be the safest option.
1. Excessive Motor Wear
When you push a compressor too far or too long, the internal parts begin to wear. Moving parts and seals are put under much more strain when they are not allowed to rest, and this will shorten the life of your equipment.
2. Part Failure
Besides the damage associated with wear, you have the risk of different parts of your compressor system failing completely. A constantly running compressor means that there is continuous pressure in the tank. Should a seal or hose fail at any point in the night, your compressor will run nonstop to try and fill an open tank.
If your compressor runs all night without stopping because of a hose split, the risk of a catastrophic motor failure goes up significantly. It’s not difficult to choose which is easier or cheaper to replace.
3. Energy Waste
Most compressors do not take a significant amount of energy to run. However, it is still wasted money that you could be spending on materials or new tools. If you were to add in the risk of a part failure and a constantly running compressor, the cost increases.
4. Moisture and Rust Buildup
A lot of part-time hobbyists and tinkerers don’t realize that when air is pulled into a compressor, moisture comes in with it. Unfortunately, some only find out when the bottom of their compressor rusts out, or water begins to spit out of their tools.
This is why compressors either have a release valve in their bottom or a built-in drainage system. If your system is constantly running or pressurized, that moisture has no way to escape.
5. Stored Energy
Most compressors built these days have safety valves and fail-safe devices built into them. These are specially designed to release the air pressure safely if the air pressure gets too high. The reason for this is because a large metal tank that is over-pressurized is essentially a bomb looking to blow.
Keep Them Running, Keep Them Safe
Whether you are painting, blowing away sawdust from your power tools, or running several pneumatic
tools at a time on a construction site, compressors are a valuable investment. Just like any other investment, it will need some attention to keep giving back. Here are some tips for keeping your investment safe and in top condition for years to come.
Shut off your compressor when not in use.
Empty the pressure after use. This will take the stress off your hoses and seals.
Drain the moisture from your compressor regularly. If you live in a humid environment, you should release the air and moisture from the valve after every use to cut down on rust buildup.
If your compressor uses oil, check and oil it regularly.
Change the oil. Your manufacturer will include information about how many hours of use between oil changes. Since it is often difficult to keep track of such things without a built-in counter, it is suggested to estimate and set a regular oil change schedule. Think of it as you would your vehicle: 3 months or 3000 miles.
Replace or clean air filters, as suggested.
If you notice a leak, find the source and fix it. Often, leaks come from thread seals that can just be tightened up. Other times, seals can go bad and only start with a small leak.
Even if there are no signs of leaks, check your fitting connections once a year.
Conclusion
Your compressor may be a fine piece of craftsmanship built to withstand the rigors of constant use. It may be built more for a few hours of use, followed by a bit of a rest. Regardless of the type you own, it is safer and more economical to shut it down when not in use. Be sure to check the duty rating of your model and always follow manufacturer guidelines.