Refrigerated Air Dryers

It chills compressed air to condense out water vapor, drains that water away, and then reheats the air slightly before it enters the shop piping. The result is a pressure dew point commonly around 38 degrees F, which prevents condensation in shop lines at normal ambient temperature.

FS-Curtis refrigerated dryers across several families — RES energy-saving models, RNB and RNP non-cycling models, RNPX, and high-inlet-temperature RNHI units — in flow capacities from roughly 10 SCFM to over 1,000 SCFM, in both air-cooled and water-cooled configurations.

Size on the actual SCFM the compressor delivers at your working pressure, not on motor horsepower, and confirm the dryer's rating at your inlet air temperature and ambient conditions. Manufacturer flow ratings assume standard conditions — hot inlet air or a hot equipment room derates the unit significantly. Alamo can verify the sizing against your actual installation.

Non-cycling dryers run their refrigeration circuit continuously regardless of load, which is simple and reliable. Cycling and energy-saving designs modulate or store cooling so the compressor runs less at part load, reducing energy use. Energy-saving models cost more up front and pay back in shops with variable air demand.

A refrigerated dryer to roughly 38 degrees F dew point is sufficient for general shop air, impact tools, and most service work. Desiccant drying is needed when the air line runs somewhere that can drop below that dew point, or when the application requires a much drier air supply than refrigerated drying can reach.

High-inlet models such as the RNHI series are built to accept air hotter than a standard dryer will tolerate — typically where there is no aftercooler, or where the aftercooler cannot pull discharge temperature down far enough. Feeding hot air into a standard dryer overwhelms it and moisture passes through.

After the compressor and aftercooler and before the distribution piping, normally with a particulate filter upstream and a coalescing filter downstream. Installing a dryer without an aftercooler ahead of it is the most common installation error and the most common cause of poor dryer performance.

Keep the condenser coil clean, verify the automatic drain actually discharges, and monitor the dew point indication if the unit provides one. A failed drain is the most frequent problem — the dryer keeps running while condensate backs up and carries downstream.