How do unloaders affect the operation of commercial AC compressors?

• A. They Increase Compressor Speed
• B. They Regulate Refrigerant Temperature
• C. They Control Capacity By Unloading Refrigerant
• D. They Serve As A Safety Switch

Answer: (C)

Unloading a compressor changes how much refrigerant the machine actually moves, which directly lowers its output to match cooling demand. By unloading, some of the cylinders or displacement are effectively taken out of service, so the compressor pumps less refrigerant each cycle. This reduces capacity while the system is under light load, improves part-load efficiency, and helps avoid unnecessary cycling. It isn’t about making the motor run faster, regulating refrigerant temperature, or acting as a safety switch; it’s a method of capacity control. That’s why the best description is that unloaders control capacity by unloading refrigerant.