Cast Air R20312HG30 — 20HP 3-Phase Rotary Screw Air Compressor, Horizontal Tank (230V or 460V)
The R20312HG30 is Cast Air's 20HP 3-phase rotary screw compressor in a horizontal tank configuration, available in either 230V or 460V 3-phase. This is the base listing for the R20312HG30 series — when you order, you specify the voltage that matches your facility's electrical service. At this HP level, that voltage choice has real operational and electrical consequences, so read the section below before placing an order.
At 20HP, this compressor sits at the top of the typical shop infrastructure spectrum. It is built for high-demand operations that have outgrown 15HP capacity or are planning for sustained peak-load production from day one.
20HP Output — What to Expect
- CFM output: The 460V variant of this model (R20312HG30-460) is confirmed at 80 CFM at 100 PSI. This figure should be treated as a strong indicator for the 230V variant as well, but call us to confirm current manufacturer specifications before purchase — compressor performance can vary slightly between production runs and configurations.
- What 80 CFM supports: Running four to five spray guns simultaneously, multiple impact wrenches across tech bays, air ratchets, die grinders, and pneumatic lift controls at the same time without meaningful pressure drop. This is the output level that lets a busy shop operate without air supply becoming the limiting factor.
- Duty cycle: Rotary screw compressors run at 100% duty cycle. This is the essential advantage over a reciprocating piston compressor at the same HP rating — no thermal cycling, no performance degradation from extended operation, no pressure waves from piston strokes. The R20312HG30 can run continuously through a full production day.
- 120-gallon horizontal tank: The large receiver provides demand buffering to absorb surge loads when multiple tools and equipment fire simultaneously. The horizontal configuration is the standard shop layout — low profile, wall-adjacent, straightforward to pipe into a distribution header.
Voltage Selection — 230V vs. 460V at 20HP
This is the single most important decision when ordering the R20312HG30. At 20HP, the voltage choice affects your electrical infrastructure requirements substantially.
- 460V 3-phase (strongly recommended where available): At 460V, the 20HP motor draws approximately 27–30 amps at full load. Smaller wire gauge, smaller breaker (60–80A range per NEC motor load rules), less heat in the circuit, and reduced electrical installation cost. If your facility has 460V 3-phase service, this is the configuration to order.
- 230V 3-phase (when 460V is not available): At 230V, the same 20HP motor draws approximately 54–60 amps at full load. This requires a dedicated circuit with a 100–125A breaker (per NEC), heavier wire gauge, and more heat generated in the electrical run. This is the correct choice only when your building does not have 460V 3-phase. It works — but the electrical infrastructure cost is higher.
- Do not guess: Have your electrician confirm your 3-phase service voltage before placing the order. Ordering the wrong voltage configuration is not a field fix — the motor is wound for a specific voltage. Call us with any questions before you order.
- Separate SKUs for each voltage: If you want the specific voltage pre-configured, order R20312HG30-460 for the 460V unit or R20312HG30-230 for the 230V unit. The base R20312HG30 listing covers the series — voltage is specified at time of order.
Who This Compressor Is For
- High-production body shops: Multiple spray booths operating daily, prep stations, and bodywork all pulling air simultaneously. If a 15HP unit is running non-stop and still cannot keep pace with peak demand, the 20HP is the correct solution.
- Large fleet maintenance facilities: Tire shops, multi-bay service lines, and fleet operations running air tools across many positions simultaneously need the sustained airflow that 20HP provides.
- Industrial and commercial operations: Pneumatic assembly, material handling, and process air supply where consistent pressure and high volume are operational requirements.
- Shops planning to expand: If you are adding a spray booth, additional bays, or new pneumatic equipment in the near term, sizing up to 20HP now avoids a second compressor purchase within a few years.
20HP vs. 15HP — Making the Right Call
- The 15HP R15312 series is the right choice if: Your shop has one active spray booth, three or fewer bays with moderate tool use, and your current compressor (if you have one) cycles off regularly during the day. The 15HP units carry a lower price point and lower electrical infrastructure cost — do not overbuy if 15HP covers your load.
- The 20HP R20312 is the right choice if: You are running multiple simultaneous spray operations, a high-bay count operation with consistent peak demand, or you have concrete plans to expand your shop's capacity in the near future.
- Not sure? Call us at 866-217-0063. Tell us your shop type, number of active bays, and what equipment you are running. We will give you an honest recommendation on which HP class fits your actual operation.
A Note on List Pricing
The listed price for the R20312HG30 ($11,842) is notably close to the 15HP vertical tank unit (R15312VG30, $11,745). This may reflect a pricing snapshot that predates recent adjustments, or promotional pricing on the 20HP series at the time of listing. Either way, confirm current pricing with us before making a purchase decision based on the listed price — we will provide accurate current pricing for both voltage configurations.
Installation Requirements
- Electrical: 3-phase power required. Voltage (230V or 460V) must match your building service. Dedicated circuit with proper breaker sizing — coordinate with a licensed electrician before delivery.
- Ventilation: A 20HP rotary screw generates significant heat during operation. The installation location must have adequate airflow. Do not install in a closed mechanical room without exhaust ventilation.
- Condensate management: At 20HP output levels, condensate production is substantial. Install an auto-drain valve on the tank. Consider a refrigerated air dryer sized for 80+ CFM if clean, dry air is required downstream — particularly for any spray work.
- Air distribution: Size your main header pipe for the CFM output of this unit. Undersized distribution is one of the most common sources of pressure complaints in shops that have the right compressor but cannot get the airflow to the tools.
Specifications
- Model: R20312HG30
- Compressor type: Rotary screw
- Horsepower: 20 HP
- Phase: 3-phase
- Available voltage: 230V or 460V (specify at time of order)
- Tank configuration: Horizontal
- Indicated CFM: Approximately 80 CFM at 100 PSI (based on 460V variant data — confirm with us prior to purchase)
- Tank capacity: 120 gallons
- List price: $11,842.20 (call to confirm current pricing)
Note: Confirm exact CFM output, operating pressure range, full dimensional specifications, and current pricing before ordering. Call us — we will get you the accurate Cast Air spec sheet and current availability.
Why Buy From OEM Diagnostic Tools?
- Specialist since 2016: We work with professional shops daily and understand what it takes to spec shop infrastructure that actually fits the operation. We will not just take your order — we will make sure you are ordering the right unit.
- Free shipping: Freight on a 20HP compressor is a meaningful cost. We include it.
- Free technical support: Call 866-217-0063. Before ordering, we help you confirm voltage requirements, verify current pricing, and answer installation questions. After delivery, we are still available.
- Full manufacturer warranty: Covered under Cast Air's warranty program, handled through us. You do not deal with the manufacturer directly.
- Honest buying guidance: If the 15HP series is the right size for your shop load, we will tell you that. If you need 20HP, we will help you spec the right voltage configuration. We sell the unit that fits your shop — not the most expensive one in the lineup.
Call 866-217-0063 for quick answers and help!
