Castair 20 HP 3Phase Rotary Screw Air Compressor 80 cfm at 100 psi 120 Gal Horiz Tank 460 R20312HG30

Cast Air R20312HG30-460 — 20HP 3-Phase Rotary Screw Air Compressor, 80 CFM at 100 PSI, 120-Gallon Horizontal Tank, 460V

80 CFM at 100 PSI. That is the number that matters. The Cast Air R20312HG30-460 is a 20HP 3-phase rotary screw compressor delivering confirmed 80 CFM at 100 PSI into a 120-gallon horizontal receiver tank, running on 460V 3-phase power. This is a production-grade shop infrastructure unit — the kind of compressor you install when your shop is running at capacity all day and you cannot afford to have air supply become the bottleneck.

The 460V configuration is the recommended choice at 20HP. Here is why that matters, and who this compressor is built for.

What 80 CFM at 100 PSI Actually Enables

• Spray guns: A single HVLP spray gun draws 12–15 CFM at operating pressure. At 80 CFM, you can run four to five spray guns simultaneously and still have 10–20 CFM available for the rest of the shop.
• Impact wrenches: A 1/2" air impact draws approximately 5–8 CFM. A 3/4" or 1" impact draws 8–15 CFM. Multiple techs running impacts simultaneously is not a problem for an 80 CFM supply.
• Air ratchets and die grinders: Die grinders are high-consumption tools at 8–12 CFM each. Body shops and custom shops running grinders heavily need real airflow, not a compressor that starves them mid-cut.
• Lifts and pneumatic equipment: Pneumatic lift controls, tire equipment, air blow guns, and utility air use adds up fast in a multi-bay shop. At 80 CFM, there is enough supply to cover the shop without tools competing for pressure.
• Real-world shop scenario: Two painters in booths (28–30 CFM), three technicians on impacts (15–24 CFM), a die grinder running (10 CFM), and miscellaneous tool use — the R20312HG30-460 handles that load without the compressor running wide open trying to keep up.

460V 3-Phase — Why This Is the Right Choice at 20HP

• Half the amperage: The same 20HP motor that draws approximately 54–60 amps on 230V 3-phase draws only 27–30 amps on 460V 3-phase. This is basic motor physics — double the voltage, half the current for identical power output.
• Smaller wire runs: Lower amperage means smaller wire gauge is acceptable for the same run length. In a large facility where the panel is not adjacent to the compressor, this reduces materials cost and installation labor significantly.
• Less heat in the circuit: Heat in electrical circuits is proportional to the square of current (I²R). Half the current means one-quarter the resistive heating in your wiring and connections. At sustained 20HP loads, this is meaningful for long-term reliability of your electrical infrastructure.
• Smaller breaker: A 460V circuit for this unit requires a breaker in the 60–80A range (per NEC motor load rules). The equivalent 230V circuit requires 100–125A. At 460V, you may be able to use an existing panel slot that 230V could not accommodate.
• When 230V is the answer instead: If your facility only has 208–240V 3-phase service, the R20312HG30-230 is the configuration you need. Do not try to adapt — the motor is wound for one voltage. Call us if you are unsure which service your building has.

Rotary Screw Design — All-Day Operation

• Continuous duty: Rotary screw compressors operate at 100% duty cycle. There are no piston rods, no valve plates, no bearings that overheat from continuous cycling. The R20312HG30-460 can run all day through your production hours without thermal shutdown or reduced output.
• Consistent pressure: Unlike reciprocating compressors that produce pulses, a rotary screw delivers a steady, continuous flow. For spray work especially, this consistency translates directly into finish quality — no micro-fluctuations in atomization pressure between strokes.
• Quiet operation: Rotary screw compressors are substantially quieter than reciprocating units of equivalent output. In a shop environment where techs and customers interact, and where painters need focused working conditions, this matters.
• Maintenance intervals: Primary service items are oil changes, air/oil separator replacement, and inlet filter service. Intervals vary by manufacturer recommendation — no valve kits or piston assemblies to manage.

120-Gallon Horizontal Tank

• Demand buffering: The 120-gallon receiver stores compressed air to absorb peak demand spikes. When multiple tools or spray guns kick on simultaneously, the receiver volume prevents the pressure drop that would otherwise occur while the compressor catches up to load.
• Horizontal layout: The standard horizontal configuration sits low and against a wall, leaving the vertical space above clear. In most shop layouts, horizontal placement is straightforward to position and pipe.
• Condensate: At 80 CFM output, moisture production from the compressor is significant. Install an automatic drain valve on the tank. Also plan for refrigerated air dryer capacity to match 80 CFM output if clean, dry air is required downstream — especially for spray paint work.

Who Needs This Compressor vs. Who Should Consider 15HP

• R20312HG30-460 is the right choice for: High-production body shops (two or more booths active daily), large fleet maintenance operations, industrial facilities, shops consistently hitting the ceiling of their current 15HP unit, and any operation planning to expand capacity in the near term.
• The 15HP R15312 series is adequate for: Single-booth body shops, moderate-demand service shops, operations with intermittent peak demand rather than sustained high output. The 15HP units are also significantly lower cost — if you are not regularly pressing the limits of 15HP output, 20HP is headroom you are paying for but not using.
• How to tell which you need: Track whether your current compressor cycles off during the workday. A compressor that never fully stops running is at its duty cycle limit and cannot handle any additional load. That is the signal to step up to 20HP.

Installation Notes

• Electrical service required: 460V 3-phase, dedicated circuit. Breaker sizing per NEC motor load rules — consult your electrician for local code compliance.
• Ventilation: Allow adequate clearance around all sides for airflow. A 20HP rotary screw generates heat that must be exhausted from the compressor room. Inadequate ventilation shortens oil life and stresses the screw element.
• Air treatment: At 80 CFM output, size your refrigerated dryer, coalescing filters, and distribution header to match this throughput. Undersized downstream equipment creates backpressure and reduces effective shop pressure.
• Header pipe sizing: For 80 CFM at moderate line lengths, consult a pipe sizing chart. Undersized header pipe is one of the most common causes of pressure drop complaints in shops that have the right compressor but undersized distribution.

Confirmed Specifications

• Model: R20312HG30-460
• Compressor type: Rotary screw
• Horsepower: 20 HP
• Phase: 3-phase
• Voltage: 460V
• Confirmed CFM: 80 CFM at 100 PSI
• Tank configuration: Horizontal
• Tank capacity: 120 gallons
• Additional specs: Contact us for full dimensional data, weight, and service interval details

Why Buy From OEM Diagnostic Tools?

• Specialist since 2016: We work with professional shops every day. We know what 80 CFM means to a body shop running two booths versus a service shop running three bays — and we give you real guidance on which unit fits your actual operation.
• Free shipping: A compressor of this size involves significant freight. We include it at no additional charge.
• Free technical support: Call 866-217-0063. Before you order, we will walk through your shop's air demand, your electrical service, and any installation questions. After delivery, we are still here.
• Full manufacturer warranty: Covered under Cast Air's standard warranty. We handle the warranty process — you work with us, not a manufacturer 1-800 line.
• Honest advice: If your shop genuinely does not need 80 CFM at 100 PSI, we will tell you that and point you to a better-fit unit. A satisfied customer who bought the right compressor is worth more to us than a return.

Call 866-217-0063 for quick answers and help!