Castair 5HP 1 Phase Rotary Screw Air Compressor 80 Gallon Horizontal R518HP75

Castair 5HP 1-Phase Rotary Screw Air Compressor 80 Gallon Horizontal — R518HP75

The Castair R518HP75 is a 5-horsepower, single-phase, 80-gallon horizontal rotary screw air compressor delivering 20 CFM at 100 PSI. It weighs 480 pounds and measures 64 inches long by 32 inches wide by 44 inches tall. Single-phase power means a standard 230V single-phase circuit — no 3-phase service required, which opens this unit up to smaller shops, residential garages, and facilities where 3-phase power simply isn't available. The horizontal tank keeps the overall height to 44 inches, making this a practical fit for shops with lower ceilings or wall mounting constraints.

Who Runs This Compressor

• Two-bay automotive shop running impacts, ratchets, and blow guns — one or two techs working simultaneously within the 20 CFM output range
• Tire and alignment shop using air tools throughout the day with continuous-duty demand that would burn up a piston compressor
• Body shop running HVLP spray guns (9-14 CFM each) or DA sanders (12-20 CFM)
• Small fabrication shop running air tools from a single-phase panel where 3-phase isn't an option
• Residential or small commercial garage needing real rotary screw reliability without the requirement for 3-phase service

20 CFM at 100 PSI — What That Covers

• 1-inch impact wrench: 10-25 CFM — a heavy 1" impact at full continuous load will challenge this unit; intermittent use works fine
• 1/2-inch impact: 4-8 CFM — comfortable, leaves headroom for other tools running simultaneously
• DA sander: 12-20 CFM — one sander running is fine; two simultaneously will draw the full 20 CFM
• HVLP spray gun: 9-14 CFM — one gun painting comfortably at the full tank capacity
• Air ratchet: 4-6 CFM — multiple ratchets can run simultaneously with this unit
• Tire inflation and general shop tools: Well within capacity

Horizontal Tank — When This Layout Works

• 44-inch height: The horizontal configuration stands 44 inches tall versus 70 inches for the vertical version (R518VP75). If your ceiling height is a constraint, horizontal is the choice.
• 64-inch length: The tradeoff is floor length. Measure your available wall space — you need roughly 5.5 feet of clear length plus service clearance.
• Stable footprint: The longer, lower profile has a low center of gravity. Suitable for locations where vertical units might feel top-heavy.
• Vertical alternative: R518VP75 is 34×26×70" and weighs the same 480 lbs. Same output, smaller floor footprint but taller.

Why Rotary Screw Over Piston at 5HP

• 100% duty cycle: A 5HP piston compressor typically runs at 50-75% duty cycle. This rotary screw runs continuously without overheating — critical for production-pace shops.
• Consistent pressure: Rotary screw output is steady. Piston units cycle between cut-in and cut-out pressure, causing noticeable pressure swings at the tool.
• Quieter operation: Rotary screws at 1725 RPM run significantly quieter than piston compressors at 3450 RPM for comparable output.
• Lower long-term maintenance cost: No pistons, rings, or valves to wear out. Maintenance is oil, filters, and separator changes on a schedule.

Castair Build Quality — What Separates This From Import Brands

• Cast iron throughout: Castair builds with cast iron — not aluminum. Handles the thermal cycling of continuous-duty operation in a real shop environment.
• Industrial 1725 RPM motor with full 15% service factor: Built for commercial use. The service factor means it can handle occasional overload without damage.
• Single solenoid air end control: No computers, no lockout codes, no proprietary control boards. One solenoid operates the air end. When something needs attention, any competent tech can work on it.
• Easy-to-read pressure and temperature gauges standard: Analog gauges on the panel — no navigating menus to check operating conditions.
• High pressure and dual high temperature shutdown standard: The unit protects itself. Both a high-pressure cutoff and dual high-temperature shutdowns are built in — not options.
• Factory-filled with Cast-Lube synthetic oil: 4,000-hour or one-year change interval. Ships ready to connect and run.
• Built-in air/oil separator with spin-on filter: Keeps oil out of the compressed air stream. Standard spin-on format — easy replacement.
• Off-shelf V-belts with adjustable tensioner: Standard belts from any industrial or farm supply. No proprietary belt ordering from the manufacturer.
• Air/oil lines in copper pipe: Not plastic hose. Copper handles heat and vibration indefinitely.
• Air-cooled aftercooler/oil cooler standard: Removable for cleaning. Cools compressed air to reduce moisture carryover and keeps oil temperature controlled.
• Hour meter standard: Track actual runtime for maintenance scheduling. Know exactly when oil and filter changes are due.
• 10-minute auto shutdown timer: If no air is drawn for 10 minutes, the unit shuts off automatically. Saves electricity on slow days or overnight.
• ASME-rated 80-gallon tank: Code-compliant. Required for most commercial insurance and inspection requirements.
• Quality name-brand magnetic starter, mounted and wired: Connect incoming 230V single-phase power — that's the installation.
• Pressure range options: Standard 135 PSI. Can be ordered at 150 or 175 PSI.
• 2-year warranty on air end, electric motor, and tank
• Made in Spicer, Minnesota

Available Configurations — Castair 5HP Rotary Screw

• R518HP75 (this unit): 5HP, 1-Phase, 80 Gal Horizontal — 20 CFM @ 100 PSI — 64×32×44" — 480 lbs
• R518VP75: 5HP, 1-Phase, 80 Gal Vertical — 20 CFM @ 100 PSI — 34×26×70" — 480 lbs
• R518HG11: 5HP, 1-Phase, 80 Gal Horizontal with G11 air end (contact for specs and pricing)
• R518VG11: 5HP, 1-Phase, 80 Gal Vertical with G11 air end
• 3-Phase 230V: R538HP75 — same layout, 3-phase 230V motor — 470 lbs
• 3-Phase 460V: R538HP75-460 — 3-phase 460V
• Step up: R718HP75 — 7.5HP, 1-Phase, 80 Gal Horizontal — 31 CFM @ 100 PSI — 555 lbs

When Does a Shop Need This vs. Stepping Up or Down?

• Right for: Single-phase power availability, 1-2 bay shop, techs running impacts and ratchets through a full shift. The 20 CFM at 100 PSI handles steady single-tech demand without strain.
• Step up to 7.5HP (R718HP75) if: Two or more techs consistently run air tools simultaneously, or you're doing continuous heavy-demand work like DA sanding production or continuous spray painting. The 7.5HP unit delivers 31 CFM @ 100 PSI — 55% more output.
• Step down if: Your actual use is intermittent, light-duty air tool work. A Castair commercial piston compressor may be a lower-cost option for truly light-duty use.
• Choose 3-phase if: Your facility has 3-phase service. The 3-phase motor (R538HP75) starts smoother, draws less amperage, and has simpler motor construction.
• Choose vertical (R518VP75) if: Floor space is limited and ceiling clearance is adequate — same output, 34" wide vs. 64" long.

Technical Specifications

• Model: R518HP75
• Horsepower: 5 HP
• Phase: 1-Phase
• Voltage: 230V (single-phase standard)
• Tank: 80 gallon, horizontal, ASME-rated
• CFM @ 100 PSI: 20
• Dimensions (L×W×H): 64" × 32" × 44"
• Weight: 480 lbs
• Compressor Type: Rotary screw
• Duty Cycle: 100%
• Standard Pressure: 135 PSI (150 or 175 PSI optional)
• Motor Speed: 1725 RPM industrial, full 15% service factor
• Drive: Belt drive, off-shelf V-belts with adjustable tensioner
• Lubrication: Oil-injected, Cast-Lube synthetic, 4,000-hour/1-year interval
• Controls: Single solenoid, pre-wired magnetic starter, analog pressure/temp gauges, hour meter, 10-minute auto shutdown
• Shutdowns: High pressure, dual high temperature (standard)
• Warranty: 2-year on air end, electric motor, and tank
• Manufacturer: Castair, Inc. (Spicer, Minnesota)

What's in the Box

• Castair rotary screw compressor assembly mounted on 80-gallon horizontal ASME tank
• Pre-wired magnetic starter and controls (connect incoming 230V 1-phase power)
• Air/oil separator with spin-on filter
• Air-cooled aftercooler/oil cooler
• Hour meter
• Pre-filled with Cast-Lube synthetic oil
• Pressure and temperature gauges installed

Recommended Maintenance Accessories

• Preventative maintenance kit (MKP75): 2 air filters, 4 oil filters, 1 separator filter, 5 gallons Cast-Lube synthetic oil — saves 10% versus buying individually
• Electronic auto tank drain (SDV03M): Eliminates manual draining; purges condensate automatically
• Vibration pads VP1004: 4"×4"×1" set of 4 — reduces vibration transmission to floor
• Ball valve BV75 (3/4"): Full-flow shutoff for the outlet line
• Metal flex hose VA075 (3/4" NPT × 18"): Isolates the tank from the plumbing, absorbs vibration

Why Buy From Air Compressor Factory Direct?

• Castair specialist since day one: We know this line, the accessories that pair with it, and the maintenance kits that keep it running
• Free shipping on qualifying orders
• Free technical support: Call 866-217-0063 — someone who understands rotary screw compressors answers
• Full manufacturer warranty honored and supported
• Honest upgrade guidance: If 7.5HP is what your shop actually needs, we'll tell you before you order the 5HP

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