Castair Heavy Duty Shop Rotary Screw Air Compressor — G11 Air End (R738VG11)
The Castair R738VG11 is a heavy-duty rotary screw compressor built around the G11 air end, available in 230V or 460V 3-phase. The G11 is a step up in air end capacity from the P75-series units used in the standard 5-10 HP rotary screw lineup. The R738VG11 targets shops that need the reliability of a rotary screw design with a more substantial air end for demanding continuous-duty applications. Priced at $7,876.95, it sits in the mid-tier rotary screw range alongside the 15 HP G30-end models.
Based on available Castair catalog data, the G11 air end is used in the 5-15 HP range of rotary screw compressors. The R738VG11 designation suggests a 7.5 HP motor pairing with the G11 air end on a vertical tank configuration. Exact CFM, PSI, tank size, weight, and dimensional specifications were not available from manufacturer pages at time of writing — contact us at 866-217-0063 for confirmed specs before ordering.
G11 Air End — What Changes From the P75
Castair uses several different air end models across their rotary screw lineup. The P75 air end covers 5-15 HP in the standard commercial lineup. The G11 is a different geometry designed for applications where sustained high-demand output is a priority. The PM kit for the G11 is the MKG11, which includes 2 air filters (RAFG11, ID 2-5/8", OD 3-7/8", HGT 3-1/8"), 4 oil filters, 1 separator filter, and 5 gallons of synthetic CAST-LUBE oil. If your shop runs the G11 air end, make sure you stock the correct RAFG11 replacement filter — it is a different physical size from P75 and D-series filters.
Air End and Drive System
- Air end: G11 rotary screw — heavier duty than P75 for demanding continuous applications
- Duty cycle: 100% rated
- Control: Single solenoid, no computers, no lockout codes
- Motor: Heavy-duty industrial 1725 RPM, 15% service factor or higher
- Drive: Off-shelf V-belts with adjustable belt tightener
- Lubrication: Factory-filled CAST-LUBE 4,000-hour / 1-year synthetic oil
- Oil filter: Spin-on type
- Air filter: Paper element (RAFG11: ID 2-5/8", OD 3-7/8", HGT 3-1/8")
Controls and Safety
- Pressure gauges: Easy-read pressure and temperature gauges standard
- Shutdowns: High pressure and dual high temperature shutdowns standard
- 10-minute shutdown timer: Standard — reduces electricity costs during idle periods
- No lockout codes: Serviceability without dealer involvement
Tank and Cooling
- Tank orientation: Available in vertical or horizontal configurations (V = vertical in model designation)
- Tank certification: ASME (USA-made)
- Air/oil separator: Built-in with spin-on filter
- Aftercooler: Air-cooled aftercooler and oil cooler standard
- Plumbing: Off-shelf copper piping
Electrical
- Voltage: 230V or 460V 3-phase (specify at order)
- Starter: Name-brand magnetic starter, factory mounted and wired
- Hour meter: Standard
Maintenance — G11 Specific Parts
- Air filter element: RAFG11 (ID: 2-5/8", OD: 3-7/8", HGT: 3-1/8")
- Oil filter: ROFD3-4-G11 spin-on
- Separator filter: RSFD3-4-6-G11-P75 spin-on
- PM kit: MKG11 — 2 air filters, 4 oil filters, 1 separator, 5 gal synthetic oil (saves 10%)
What Is in the Box
- Castair R738VG11 rotary screw compressor, fully assembled
- ASME-certified tank (USA-made), vertical configuration
- Air-cooled aftercooler and oil cooler
- Magnetic starter and controls, factory wired
- Hour meter
- Pressure and temperature gauges
- Factory fill CAST-LUBE synthetic oil
Vibration pads, ball valve, and flex hose are recommended accessories, available separately or factory-mounted.
Available Configurations — G-Series Rotary Screw
- R738VG11 (this unit) — 7.5 HP, G11 air end, vertical, 230V or 460V
- R15312VG30 — 15 HP, G30 air end, 120 gal vertical, 58 CFM, 44x32x73, 930 lbs
- R15312HG30 — 15 HP, G30 air end, 120 gal horizontal, 58 CFM, 69x33x55, 930 lbs
- R20312VG30 — 20 HP, G30 air end, 120 gal vertical, 80 CFM, 44x32x73, 930 lbs
- R25312VG30 — 25 HP, G30 air end, 120 gal vertical, 105 CFM, 44x32x73, 1045 lbs
- R30312VG30 — 30 HP, G30 air end, 120 gal, 130 CFM, 1065 lbs
When Does a Shop Need the G11 vs. Other Air Ends?
The G11 air end is suited for shops that need reliable continuous-duty output and prefer the G-series geometry over the D or P75 series. If your operation runs at or near 100% duty for extended periods — automated production, continuous spray application, or high-cycle pneumatic equipment — the G-series air ends are worth considering over the standard P75 models in the same HP bracket.
If you need higher CFM output (above 50 CFM), step up to the G30-end 15-25 HP models. If your air demand is moderate and intermittent, the standard P75-based R738VP75 or R738HP75 at $10,017 to $10,223 may serve you equally well at lower cost.
Technical Specifications
- Model: R738VG11
- Air end: G11 rotary screw
- Horsepower: 7.5 HP
- Phase: 3-phase
- Voltage: 230V or 460V (specify at order)
- Standard operating pressure: 135 PSI (150 or 175 PSI available)
- Duty cycle: 100%
- Tank orientation: Vertical
- Tank certification: ASME (USA-made)
- Motor speed: 1725 RPM
- Motor service factor: 15% or higher
- Oil: CAST-LUBE synthetic, 4,000-hour / 1-year service interval
- Warranty: 2 years on air end, electric motor, and tank
- Air filter: RAFG11 (ID 2-5/8", OD 3-7/8", HGT 3-1/8")
CFM output, tank size, weight, and exact dimensions: contact us at 866-217-0063 for confirmed specifications.
Why Buy From Air Compressor Factory Direct?
- Castair specialists: We carry the full lineup including G-series air end models and corresponding filter parts
- Free shipping to commercial addresses
- Free tech support: 866-217-0063 — we can confirm G11 specs and compare to your actual CFM requirements
- Full 2-year warranty on air end, motor, and tank
- Parts availability: RAFG11 air filter, MKG11 PM kit, and G11-specific oil and separator filters stocked
Call 866-217-0063 for quick answers and help!
