The Castair #AOC4 is the complete factory-installed options package for Cast Air C4-series compressors. The C4 pump covers the 20 to 30 HP range in Cast Air's industrial lineup — a V4-configuration two-stage cast iron pump producing approximately 72-93 CFM at operating pressures, running at low RPM for long service life. This bundle includes aftercooling, automatic drains, hour metering, dual control, intake silencing, and vibration isolation factory-installed and matched to C4 output. Bundle pricing saves 10% over purchasing individual options.
The C4 is the largest pump in Cast Air's standard industrial lineup. It is the right choice when the C3 at 15 HP is genuinely undersized — when your facility routinely demands more than 55-60 CFM during production hours. At this size, proper aftercooling and moisture management are critical: the volume of water vapor produced by a 20-30 HP compressor running near capacity is substantial, and a properly spec'd aftercooler and drain system prevents that moisture from reaching your tools and equipment.
What the AOC4 Bundle Includes
Aftercooler System
- Belt Guard Aftercooler (#BGAC3M): Factory-mounted, rated for 20 HP and above. Matched to C4 output volume and heat load. Cools compressed air discharge from pump temperatures (often 300°F+) toward ambient, removing approximately 65% of water vapor. Max 250 PSIG operating pressure, max 350°F inlet temperature.
Automatic Drain System
- Air-Operated Auto Drain (#ADVSM): Automatic condensate purge on each compressor cycle, powered by discharge pressure. Complete installation kit included. No separate electrical supply required.
- Electronic Auto Drain (#SDV03M): 115V timer-controlled solenoid drain with inline strainer. Handles off-hours condensate accumulation — on a large-tank C4 installation, this is not optional. Condensate sitting in a 240-gallon tank overnight corrodes from the inside out.
Hour Meter
- Hour Meter: Voltage-matched elapsed time meter for your electrical service. Tracks actual run hours for maintenance scheduling. At 20-30 HP, this compressor is a multi-thousand dollar investment — hour-based maintenance scheduling protects it. Oil changes, belt inspection, valve service, and unloader checks all run on hour intervals.
Dual Control
- Dual Control (#DC3): Start/stop and constant-speed load/unload operation modes. On a 20-30 HP motor, limiting starts per hour is an important part of motor life management. Constant-speed unloading during sustained demand periods keeps starts to a minimum. Dual control gives you the flexibility to choose the right mode for your operating pattern.
Intake Noise Silencer
- Intake Noise Silencer (#SA100M): Factory-mounted intake silencer. Reduces C4 pump intake noise without restricting airflow to the pump cylinders.
Vibration Management
- Vibration Pads (#VP1004): Set of four heavy rubber isolation pads. Required for a C4-scale installation — protects the building structure, tank welds, and all threaded connections and piping from vibration fatigue.
Right From Start Kit
- #RFS003: Cast Air startup kit for C4 pump family. Correct oil fill and break-in procedure documentation. Follow it — the C4 is a significant machine and proper break-in matters.
Who Needs the AOC4 Bundle
The AOC4 is for facilities installing a Cast Air C4 compressor where sustained high-volume air demand is the daily reality. If you are looking at a C4, you have already determined that a C3 or smaller will not keep up with your operation. Common applications include large body shops, manufacturing facilities, commercial tire chains, and industrial processes with high CFM requirements.
Manufacturer specifications pending on voltage configuration for AOC4 — contact us at 866-217-0063 or Cast Air directly at (320) 796-0851 to confirm the electrical service for your specific C4 application before ordering.
AOC4 vs. Stepping Down
- AOC3: C3 pump, 15 HP, approximately 50 CFM at 175 PSI. If your real-world demand stays under 55 CFM, the C3 is the right size. A properly sized C3 outperforms an oversized C4 running at low duty cycle in efficiency and reliability.
- AOC4 (this product): C4 pump, 20-30 HP, 70+ CFM at pressure. Correct when demand genuinely exceeds C3 capacity.
Technical Specifications
- Compatible Compressor Family: Cast Air C4 (20-30 HP)
- Aftercooler: #BGAC3M (rated 20 HP+)
- Max Operating Pressure: 250 PSIG
- Max Inlet Air Temperature: 350°F
- C4 Pump CFM (reference, 20 HP): approximately 93 CFM at 0 PSI / 72 CFM at 175 PSI
- C4 Oil Capacity: 1 gallon
- Auto Drain: Air-operated #ADVSM + Electronic #SDV03M (115V)
- Dual Control: #DC3
- Intake Silencer: #SA100M
- Vibration Pads: #VP1004 (set of 4)
- Startup Kit: #RFS003
- Bundle Savings: 10% off individual component pricing
- Note: Voltage specification — contact Cast Air at (320) 796-0851 to confirm electrical service requirement for your C4 configuration
What is in the Box
Factory-installed option package. All components are mounted and tested on your C4 compressor at the factory before shipment. Contact us at 866-217-0063 or Cast Air at (320) 796-0851 for current pricing and lead times on C4 configurations.
Why Buy From OEM Diagnostic Tools?
We have specialized in professional shop equipment since 2016. Free shipping, free pre-sale technical support at 866-217-0063, and full Cast Air manufacturer warranty. For a C4-scale compressor investment, call us before you order — we will confirm CFM requirements, electrical service specs, and the correct configuration for your facility.
Call 866-217-0063 for quick answers and help!
