ABAC AS-20S253BMD 20 HP Rotary Screw Air Compressor - Base Mount with Dryer, 125 PSI, 81.9 CFM, 67 dBA

The ABAC AS-20S253BMD pairs a 20 HP rotary screw compressor with a matched refrigerated dryer on one base, so the air leaving the package is already dry and ready to pipe. It delivers 81.9 CFM at 125 PSI and runs at 67 dBA. This is the base mount build, which means no receiver on board: it feeds a tank you already own, or one sized to the demand you actually have. Power is 208-230-460V three-phase.

Key specifications

• Model: AS-20S253BMD (part number 4152028461)
• Motor: 20 HP, energy efficient
• Air delivery: 81.9 CFM, free air delivery per ISO 1217 Annex C
• Working pressure: 125 PSI
• Noise level: 67 dBA, measured per ISO 2151:2004
• Integrated refrigerated air dryer, matched, mounted and wired at the factory
• Mounting: base mount with integrated dryer, no tank
• Power supply: 208-230-460/3/60
• Weight: 798 lbs
• Dimensions (L x W x H): 55 x 31 x 49 in
• Fully integrated aluminum block air end
• Eco friendly vertical oil separation
• Duty: continuous
• Brand: ABAC, part of the Atlas Copco group

Typical applications

Production and fabrication floors, machine shops running several cells at once, automotive and fleet service bays, tire and truck shops, cabinet and woodworking shops, and spray finishing or powder coating work where water in the line spoils tools, air logic or finish quality. ABAC positions the AS-B 20S to 30 HP range at demanding automotive and industrial work needing a reliable and continuous supply, and that is the right way to read this machine. A rotary screw is built for continuous duty, so it holds a steady line pressure through a full shift instead of recovering between jobs, and drying the air at the compressor keeps condensate out of the distribution piping rather than leaving it for traps and filters downstream to catch.

How it compares

The S in AS-20S is the difference worth understanding: against the standard AS-20253BM at the same 20 HP and the same 125 PSI, this machine delivers 81.9 CFM instead of 60.6 CFM and runs at 67 dBA instead of 71 dBA. That is roughly 21 CFM more air from the same motor rating, which is the step shops make when sandblasting, plasma cutting or several bays running at once keep pulling a standard 20 HP unit down. Against the plain AS-20S253BM base mount, this BMD adds the dryer already matched, mounted and wired, at 798 lbs and 55 inches long rather than 690 lbs and 44 inches. If you would rather the receiver came with it, the AS-20S253TMD is the same compressor and dryer on a 132 gallon tank at 1297 lbs. For higher line pressure, the 150 PSI AS-20S503BMD trades flow for pressure at 78 CFM on the same 798 lb base. Stepping up the range costs nothing in floor space, because the 25 and 30 HP base mount machines with dryer share the same 55 x 31 x 49 in cabinet: the AS-25253BMD carries 98.9 CFM at 69 dBA and 831 lbs.

Installation notes

At 55 x 31 x 49 inches and 798 lbs this is a set in place unit, so check the door width and the floor route in advance. Run it on a dedicated three-phase circuit sized to the motor nameplate, leave clear space on the cooling air side so the package is not recirculating its own hot air, and route the dryer condensate to a drain point or an oil water separator rather than onto the shop floor. Oil, oil filter, air filter and separator element are the scheduled service items on a screw package, and keeping a spare set on the shelf stops a routine service from turning into downtime.

Sizing the receiver

A base mount unit needs an air receiver to buffer demand and to let the dryer work against a steady flow. The tank has to suit the duty cycle and the size of the largest single air draw on the system, and an undersized one will make a 20 HP screw cycle more than it should. ABAC's own tank mount build of this machine, the AS-20S253TMD, pairs it with a 132 gallon receiver, which is a sound starting point when sizing a tank for 81.9 CFM. See our vertical air receiver tanks and horizontal air receiver tanks, and settle the receiver before the machine arrives so the installer can pipe it in on the same visit.

Part of the ABAC AS-B screw range from the Atlas Copco group, built around a fully integrated aluminum block, eco friendly vertical oil separation technology and an energy efficient motor, with an air end designed to limit air loss, noise and vibration. See the rest of our rotary screw air compressors, our fixed speed rotary screw air compressors and the full refrigerated air dryer range.

CFM measured per ISO 1217 Annex C. Noise measured per ISO 2151:2004 using ISO 9614/2 (sound intensity method).