Cast Air R15312HG30-230 — 15HP 3-Phase Rotary Screw Air Compressor, 120-Gallon Horizontal Tank, 230V
The Cast Air R15312HG30-230 steps up to 15 horsepower with a 120-gallon horizontal air receiver, running on 230V 3-phase power. This is the machine for shops where a 10HP unit is not enough — where you are running three or more air tools simultaneously, operating spray booths with high-CFM requirements, or running a multi-bay facility where demand consistently outpaces what a 10HP compressor can deliver. The 120-gallon horizontal tank gives you serious reserve capacity. And at 230V 3-phase, it drops onto the same voltage service as a 10HP 230V unit, which simplifies the upgrade path for shops already on that service.
Note: CFM output, exact weight, dimensions, and additional specifications are pending manufacturer confirmation. Typical output for a 15HP rotary screw is in the range of 58-65 CFM at 100 PSI, but we are not publishing an unconfirmed spec. Contact us at 866-217-0063 for confirmed performance data before ordering.
Why 15HP Instead of 10HP — The Real Difference
The jump from 10HP to 15HP is not subtle. Here is what changes in practice:
- CFM output — A 10HP rotary screw produces approximately 40 CFM at 100 PSI (confirmed on the R1038VP75-460). A 15HP unit typically produces 58-65 CFM at 100 PSI. That is roughly a 45-60% increase in airflow capacity.
- Simultaneous tool load — At 40 CFM, running two HVLP spray guns or three DA sanders is at the margin. At 60+ CFM, you have meaningful headroom for multi-tool operation without pressure drop.
- Spray booth operation — High-volume spray guns (particularly waterborne systems) can demand 15-25 CFM at the gun alone. A spray booth plus in-use hand tools can push 40-50 CFM sustained demand. The 15HP unit handles this; the 10HP is borderline.
- Recovery time after peak demand — A higher-output compressor recharges the tank faster after a high-demand event, which means fewer situations where pressure sags mid-job.
120-Gallon Horizontal Tank — Capacity and Layout Considerations
The horizontal configuration on this unit is a deliberate tradeoff compared to vertical-tank models:
- Reserve capacity — 120 gallons of stored air is substantially more than the 75-80 gallon vertical tanks on the 10HP units. More reserve means the compressor handles demand spikes without the motor having to engage immediately, which reduces cycling and extends compressor life.
- Multi-tool operations — Shops running three or more tools simultaneously benefit from larger tank capacity because the stored air absorbs burst demand before the compressor motor has to respond. This keeps pressure steady at the tools even during peak use.
- Floor footprint tradeoff — A horizontal 120-gallon tank occupies more floor space than a vertical 75-gallon tank. This unit needs a proper installation location with adequate clearance on all sides for ventilation and service access. Plan the space before ordering.
- Stability — Horizontal tanks sit low and are inherently stable. No concerns about tipping in high-vibration environments.
Who Steps Up to 15HP
The R15312HG30-230 is the right unit when:
- You are running a spray booth and other shop tools at the same time — A painter in the booth plus a technician on an impact gun elsewhere in the shop draws more than a 10HP unit can sustain without pressure drop.
- You have three or more bays in active production simultaneously — At full production, three bays running impact tools, lifts, and air ratchets can approach or exceed 40 CFM. The 15HP unit gives you headroom.
- Your 10HP compressor cycles constantly and cannot maintain 90 PSI at the tools during peak hours — This is the clearest signal that you have outgrown your current unit.
- You plan to expand operations — Buying the 15HP now instead of the 10HP means the compressor infrastructure does not become the bottleneck as you add bays or equipment.
- You are upgrading from a 10HP unit on 230V 3-phase service — The R15312HG30-230 runs on the same voltage. In many cases, the existing panel, breaker slot, and wiring gauge will accommodate the upgrade with only a breaker change. Your electrician will need to confirm amperage requirements.
230V 3-Phase — Installation and Upgrade Path
Running at 230V 3-phase has a specific practical advantage for shops upgrading from a 10HP 230V unit:
- Same voltage, different amperage — Your existing 3-phase 230V service is already the right voltage. What changes is the amperage draw. A 15HP motor at 230V 3-phase draws approximately 42-46 amps at full load, compared to roughly 28-32 amps for a 10HP. Have your electrician verify that your panel has a breaker slot and capacity for this load.
- Wire gauge — The higher amperage may require upgrading the wire run from the panel to the compressor. This depends on wire length and the gauge originally installed for the 10HP unit. Do not assume the existing wire is adequate for 15HP without confirming with an electrician.
- 460V version comparison — If a 460V version of this model is available, the 460V unit would draw approximately half the amperage (21-23 amps) for the same horsepower. If your facility has 460V 3-phase service, that version is worth considering for reduced wiring requirements. Call us to confirm current availability.
Rotary Screw Continuous-Duty Performance
- 100% duty cycle — This compressor runs all day without a required cool-down cycle. Piston compressors at 15HP are typically rated at 50-75% duty. In a full-production shop, continuous duty is not optional — it is the baseline requirement.
- Consistent output — Rotary screw compressors maintain steady CFM output throughout the operating cycle, unlike piston units that produce slightly variable flow as they cycle.
- Lower noise profile — 15HP rotary screw units run significantly quieter than 15HP piston compressors. This matters in a shop environment where communication between technicians is constant.
- Reduced vibration — No reciprocating components means less vibration transmitted to the floor. Better for nearby precision equipment and for the longevity of air line connections.
Comparison: R15312HG30-230 vs. 10HP Units
- R1038VP75-230 (10HP, 230V, 75-gal vertical) — Correct for two-bay shops with moderate simultaneous demand. Outgrown when pressure drops during peak hours or when a spray booth is added.
- R1038VP75-460 (10HP, 460V, 80-gal vertical, 40 CFM confirmed) — Same output class as the 230V 10HP, different voltage. Right for shops on 460V service that do not yet need 15HP output.
- R15312HG30-230 (this unit — 15HP, 230V, 120-gal horizontal) — Step up when 10HP cannot keep up with production demand. Larger tank. Higher output. Same voltage service as 10HP 230V — easier upgrade path.
Installation Notes
- Dedicated 230V 3-phase circuit required — Breaker sized per NEC at 125% of motor FLA. Confirm with a licensed electrician before installation.
- Floor space planning — A horizontal 120-gallon tank is a large piece of equipment. Measure your available space and confirm clearance for the unit plus service access before ordering. Freight delivery will require appropriate unloading equipment.
- Ventilation — 15HP generates meaningful heat during continuous operation. The installation area must have adequate airflow. Do not enclose the unit without a planned ventilation solution.
- Condensate management — A 120-gallon tank accumulates significant condensate. Install an automatic drain valve or commit to a regular manual drain schedule. Condensate left in the tank causes rust and contaminates downstream air quality.
- Air distribution system — Size your shop air lines for the CFM output of this unit. Undersized main lines will create back-pressure and negate the performance of a properly sized compressor.
What's in the Box
Confirm complete contents with current manufacturer documentation at time of order.
- 15HP rotary screw compressor and motor assembly
- 120-gallon horizontal air receiver tank
- Tank pressure gauge
- Safety relief valve
- Motor starter and control panel
- Initial oil charge (confirm with product documentation)
- Installation and maintenance manual
Why Buy From OEM Diagnostic Tools?
OEM Diagnostic Tools has been supplying professional shop equipment since 2016. A 15HP rotary screw compressor is a significant infrastructure purchase — not something to buy based on a spec sheet alone. When you call us, you get a conversation about your actual shop load, your electrical service, your floor space, and whether this unit is the right fit or whether you should be looking at a different configuration. We carry multiple compressor options and will tell you honestly which one fits your application.
- Free shipping on this unit (freight delivery — confirm delivery access, lift gate requirements, and unloading equipment at your location before ordering)
- Free tech support at 866-217-0063 — call before you order if you have sizing, electrical, or installation questions
- Full manufacturer warranty honored
- Honest guidance on 10HP vs. 15HP — if the 10HP unit covers your actual demand, we will tell you and save you the money
Call 866-217-0063 for quick answers and help!
