Choosing an air compressor may sound like a pretty easy task to those who do not really understand. But if a customer is not careful in their selection a salesperson can make quite a large commission selling you a much bigger unit than what is actually needed.
The flip side of that of course, is that you may get home only to realize that the air compressor you purchased is not big enough to meet your needs. This can be eliminated if you do a small amount of research before going to the store. Actually, purchasing one online can be less expensive, but you have to know what you want before you begin shopping.
Buying the wrong air compressor will not only disappoint you (regarding utility or power or air production), but it can also prepare you for huge maintenance bills in the future.
Here are ten things to think about BEFORE going to the store to buy a reciprocating air compressor.
My recommendations will be a good air compressor.
1. Type of compressor
There are three types of reciprocating air compressors:
- * Two-stage compressors
- * Single stage compressors
- * Twin compressors
The single-stage units compress the air at once, from the ambient pressure to the final pressure. Typically, they reach 20 CFM (cubic feet per minute) at a pressure of 125 psi.
To get more power, you will need a two-stage compressor. A two-stage compressor uses two stages to compress the air to the final pressure. This means that your compressor will have two cylinders / pistons.
The large cylinder is the low-pressure stage, while the small cylinder is the high stage. Between the stages, the air cools.
Two-stage air compressors reach a capacity of approximately 50 CFM to approximately 175 psi.If you need a one or two stage compressor, it ultimately depends on the amount of capacity (cubic foot per minute) you need.
2. Capacity and pressure
The capacity (CFM) and the pressure of the air compressor are the two most important specifications.To know the capacity you need, simply add the air consumption of all the air tools you will use. Small tools such as nailers use only a little air, while large tools such as sanders and the grinder use a lot of compressed air!
To know the pressure you need, check again the specifications of the air tools you plan to use. The highest pressure required dictates the pressure you need.
It is always smart to buy a compressor that is capable of delivering more than you need. It will probably add more tools in the future, and almost all compressed air systems will have a leaky hose or a coupling somewhere!
3. Horse of power
YOU DO NOT NEED to know the power of the air compressor. The power is the result of the required pressure and capacity you need and not the other way around. Do not look at horsepower. Look at the capacity (CFM) and the pressure (psi).
4. Electrical connections
I would not be the first happy owner of a new compressor that comes home with an air compressor that can’t connect! Know the voltage that you have at home. Know the maximum current your wiring can handle. Do you have a single-phase or three-phase power?
Install additional electrical wiring (or even have the 3-phase power installed in your home!) It can be more expensive than the air compressor itself!
Do you plan to install an air compressor inside or outside?
A reciprocating compressor makes a lot of noise. Always check the compressor noise level before buying one. If you are buying a compressor in a store, ask them to run it so you can hear how it sounds.
To reduce noise, you can make an enclosure around the compressor. Be sure to add enough ventilation holes (and a fan if necessary). An air compressor creates a lot of heat, so proper cooling is required!
6. Tank size
Most reciprocating compressors come with a 40 to 80-gallon tank, which is fine. A larger tank is always better. A larger tank means there is a larger compressed air cushion.
A larger air cushion is useful when you use large tools that use more air than the capacity of your compressor. The pressure will decrease more slowly with a larger air tank.
7. Compressed air filters
How clean does your compressed air need?
The compressed air is hot, wet and dirty. According to its application, it must filter it and eliminate water and oil. If you use compressed air to paint with paint, you do not want it to contain oil, water or dust in your compressed air; the air must be very clean. If you only use it to feed air tools, you do not want water in your compressed air, but you do not care about the oil.
There are filters available to remove water (drops), oil and dust. To get drier compressed air, you need to obtain a compressed air dryer.
8. Other options and extras
There is a list of options that you should think about. Do you need them or are they optional?
- * Pressure regulators: to regulate the pressure of the tank at a stable and low pressure
- * Size and number of air connections
- * Vertical or horizontal tank
- * Manual or automatic drains
Most stores (online) will drop their new air compressor into your driveway. You will have to take it to your garage or wherever you want to place it yourself.
Your new air compressor will probably come with a wooden platform. You can choose to keep it on the platform or remove the platform.
Think about how you will take your 600 lbs air compressor to its place before buying it!
10. Work cycle
Last but not least!
The duty cycle is the percentage of time that your compressor can operate. Most single-stage compressors have a duty cycle of only 50%. This means that when you run your compressor for 5 minutes, you need 5 minutes to cool down. Most double stage compressors have a 100% duty cycle. They can operate 24 hours a day when necessary. If a compressor has a 100% duty cycle, it is often announced. Be careful when the work cycle is not mentioned. It’s probably only 50%!
As you can see, there are many things to think about when buying a new air compressor. The above list will help you make a good decision. If you can not choose between two models, always choose the largest unit.