ABAC AS-5251TM 5 HP Rotary Screw Air Compressor - 71 Gallon Tank Mount, 125 PSI, 20.3 CFM, 63 dBA

The ABAC AS-5251TM is a 5 HP rotary screw air compressor built for shops that run air continuously rather than in bursts. It delivers 20.3 CFM at 125 PSI and runs at 63 dBA, quiet enough to sit in the work area instead of a separate compressor room. The compressor arrives already mounted on a 71 gallon air receiver, so it lands as one 56 x 23 x 55 in package with no separate tank to source or plumb. Choose 230V single-phase (AS-5251TM) or 208-230-460V three-phase (AS-5253TM).

Key specifications

• Models: AS-5251TM (part number 4152044119, 230V single-phase) and AS-5253TM (part number 4152043889, 208-230-460V three-phase)
• Motor: 5 HP, energy efficient
• Air delivery: 20.3 CFM
• Maximum working pressure: 125 PSI
• Noise level: 63 dBA
• Mounting: tank mount on a 71 gallon air receiver
• Power supply: 230/1/60 or 208-230-460/3/60
• Weight: 485 lbs
• Dimensions (L x W x H): 56 x 23 x 55 in
• Fully integrated aluminum block air end
• Three stage vertical oil separation technology
• Digital controller with menu driven operation and programmed maintenance
• Duty cycle: rated for continuous running
• Brand: ABAC, part of the Atlas Copco group

Why a screw instead of another piston

A piston compressor builds air in bursts and needs time to cool between them. A rotary screw turns continuously, so it holds a steady line pressure through a full shift instead of sagging and recovering between jobs. That is the reason shops move off a piston machine that is cycling hard, running hot and filling the room with noise. ABAC builds the AS-B air end as a fully integrated aluminum block with a three stage vertical oil separation process, which keeps oil carryover and condensation low, and pairs it with an energy efficient motor and a digital controller that tracks the service intervals on the panel rather than on a clipboard. The trade is that a screw dislikes short cycling, so it wants a receiver sized to its output and a demand pattern that keeps it loaded. The 71 gallon tank on this build is matched to the air end for exactly that reason.

How it compares

The same 5 HP air end is sold three ways. The AS-5251BM base mount is the compressor on its own, 335 lbs on a 32 x 24 x 40 in footprint, for a shop that already has a receiver. This tank mount build adds the 71 gallon receiver and comes in at 485 lbs. The AS-5251TMD adds a refrigerated dryer on the same 56 x 23 x 55 in frame at 571 lbs. If your tools need line pressure above 125 PSI, the AS-5501TM 150 PSI build trades airflow for pressure at 17.4 CFM. If you need more air, the 7.5 HP AS-7.5251TM7 delivers 30.5 CFM on the same 71 gallon platform at 507 lbs and 67 dBA. Pick on CFM first, then on pressure, then on whether you want the tank and the dryer in the same package.

Typical applications

ABAC rates the AS-B range for professional and industrial work where the air supply has to be continuous and the operating conditions are demanding: heavy assembly, production line assembly, and cleaning and preparation. In practice that means automotive service bays, tire shops, small production and fabrication floors, cabinet and woodworking shops, and any operation where a piston compressor is cycling too hard to keep up. At 20.3 CFM the AS-5251TM suits a bay running impact tools, an orbital sander or a small plasma cutter, with headroom for intermittent work at a second station. It is not the machine for sandblasting or for several impact wrenches drawing at once; that is where the 7.5 HP and 10 HP builds start.

Installation and air treatment

A screw compressor delivers warm, wet air, so plan the downstream side with it. Leave clearance on the cooling air side, keep the room out of the extremes of heat, and run the unit on its own circuit sized to the motor nameplate. At 485 lbs this arrives on a pallet and wants a forklift or a pallet jack at delivery, so allow for the 56 x 23 x 55 in footprint plus service clearance when you pick the spot. Add a COOL 25 refrigerated air dryer and a filter regulator if the air goes to paint, tires or anything that hates water; the COOL 25 runs on a 115V outlet, so it plugs in beside the compressor without new wiring, and it covers the full 20.3 CFM output. The AS-5251TMD above is the same machine with that dryer already integrated and already matched to the output. Oil, oil filter and separator element are the service items, so keep a spare set on the shelf. Call us with your tool list and duty cycle and we will check this machine against the demand before you pipe it in.

Part of the ABAC AS-B 5 to 20 HP screw range from the Atlas Copco group. See the full rotary screw air compressor range, the fixed speed screw compressors, all 5 HP air compressors, or our refrigerated air dryers.

CFM measured per ISO 1217 Annex C, quoted at 109 PSI for 125 PSI maximum units. Noise measured per ISO 2151:2004 using ISO 9614/2 (sound intensity method).