ABAC AB5-21120D 10 HP Two-Stage Duplex Air Compressor - 120 Gallon Horizontal, 175 PSI, 33.2 CFM

The ABAC AB5-21120D mounts two independent 5 HP motor and pump assemblies on a single 120 gallon horizontal ASME tank. The controller alternates between pumps to even out wear, or runs both together when demand spikes, delivering a combined 33.2 CFM (16.6 CFM per pump) at a maximum 175 PSI. If one pump ever needs service, the other keeps the shop running: redundancy that a single-pump compressor simply cannot offer.

Key specifications

• Models: AB5-21120D 230V single-phase (part 8090304224), AB5-23120D 230V three-phase (part 8090304232), AB5-43120D 460V three-phase (part 8090304240)
• Power: 10 HP total, two 5 HP motors
• Pumps: two T39 two-stage hybrid pumps, aluminum with cast iron cylinders
• Air delivery: 33.2 CFM combined, 16.6 CFM per pump at max pressure
• Maximum pressure: 175 PSI
• Tank: 120 gallon horizontal, ASME tank and safety valves
• Alternating or simultaneous pump operation for uptime and peak capacity
• Fully programmable control panel settings
• Aluminum heads and aftercoolers, fully enclosed belt guards
• Dual start/stop pressure switch controls, magnetic starters
• Weight: 892 lbs | Dimensions: 25 x 79 x 55 in
• Warranty: 2 year full, assembled in the USA

How it compares

Within the Hybrid Pro duplex range the only variable is capacity, because the footprint does not change. The AB7-21120D pairs two 7.5 HP pumps for 44.6 CFM on the same 120 gallon horizontal tank and the same 25 x 79 x 55 in floor space, at 910 lbs against this machine's 892. Against a single machine, the AB5-2180VP runs one 5 HP T39 pump at 16.6 CFM on an 80 gallon vertical tank, so the duplex doubles that output and adds the fallback a single-pump compressor cannot give you. If the duty cycle calls for full cast iron rather than the hybrid T39, the ABC5-21120HD Ironman duplex is also 10 HP on 120 gallons, at 32 CFM with C1 cast iron pumps.

Typical applications

ABAC positions the Hybrid Pro Duplex for work with a high variation in air demand, anywhere from intermittent duty up to 100 percent duty: hammering, spraying, grinding, fastening, orbital sanding and general equipment operation. Those are surge loads rather than steady ones, which is exactly where a duplex earns its price. One pump carries the baseline and the second joins only when the line calls for it, so neither motor spends the day short cycling the way a single large compressor would. Production shops, multi-bay service centers and any floor where an air outage stops the whole operation are the usual homes for this machine. Where the panel offers three-phase, the 230V or 460V three-phase build is the better long term choice, because a three-phase motor draws less current per leg and runs cooler under a hard duty cycle.

Two-stage compression sends warm, wet air down the line, so size a refrigerated dryer above the compressor's output rather than to the pipe. The ABAC COOL 35 is the smallest dryer in the COOL range that covers 33.2 CFM, and the COOL 50 leaves room to spare in a warm shop. Part of ABAC's 2-Stage Hybrid Pro Duplex range from the Atlas Copco group. Browse the rest of our piston air compressors and our refrigerated air dryers.