The two major types of airless paint sprayers have either piston or diaphragm pumps. Piston pumps may use either single-stroke or double-stroke pistons. The advantages of piston sprayers include the better atomization of paint, the possibility of using longer hoses and the ease of repair. Some advantages of diaphragm pump sprayers are high flow rates and the pressure control available no matter the pressure being used.
While diaphragm pump sprayers run continuously, piston pump sprayers run on command. The diaphragm pump variety is more economical for the initial purchase, but the piston pump variety is cheaper to maintain. Piston pumps perform better with high viscosity coatings. Diaphragm models, which are more difficult to prime, have a slower startup.
Diaphragm pumps are more likely to leak air into the paint, which can create an erratic flow. They may also leak hydraulic fluid into the paint. Piston pump sprayers can experience flow fluctuations at lower pressures. Piston pumps are typically sturdier, making them more popular with professional contractors; 85 percent of professional contractors use piston pumps.
Airless paint sprayers commonly operate at between 300 and 7500 pounds per square inch. Different tips are available to produce varying spray patterns. Airless pumps use electric, pneumatic or hydraulic motors.