Castair I30324HC4Z-S: 30HP 3-Phase Industrial Air Compressor — 240 Gallon Horizontal with Mounted Starter
The Castair I30324HC4Z-S is the top of Castair's standard Industrial Series lineup: 30 horsepower, 3-phase, 240-gallon horizontal, with factory-mounted magnetic motor starter. At 794 RPM, the C4 pump delivers 128 CFM free air and 105 CFM at 175 PSI. This is not a compressor for a small shop — it is sized for large production facilities, major body shops running multiple spray booths, truck service operations, or any environment where air demand is high and pressure consistency is non-negotiable.
The same C4 pump platform runs across the 20, 25, and 30HP configurations. At 30HP and 794 RPM, the pump is running at the upper end of the C4's rated range (15-25HP nominal, with the 30HP representing extended capacity on this platform). The result is 105 CFM at 175 PSI — enough to simultaneously support a spray booth, 3-4 impact gun stations, a plasma cutter with air assist, and general shop air demand without the system struggling to recover.
The 240-gallon ASME horizontal tank at 90 x 39 x 70 inches weighs 1,750 lbs. This is freight delivery only — plan for a loading dock or forklift at your installation site. This is also a permanent installation compressor: once it is set, it stays.
C4 Pump — Specifications
Construction
- Pump designation: C4 — Two-stage, V4 cylinder configuration
- Pump RPM at 30HP: 794
- Construction: 100% cast iron — cylinders, heads, valve plates, crankcase
- Flywheel: 13-3B
- Oil capacity: 1 gallon
- Bearings: Tapered roller bearings at both crankshaft ends
- Connecting rods: Precision steel with automotive-type rod insert bearings
- Valves: Disc and spring — field-replaceable
- Pistons: 4-ring configuration
- Unloader: Centrifugal — loadless start-up every cycle
Tank and Frame
- Tank capacity: 240 gallons, horizontal
- Dimensions: 90 x 39 x 70 inches
- Weight: 1,750 lbs
- Tank construction: Powder-coated ASME-rated steel with channel saddle frame
- Safety valve: ASME-rated, factory installed
- Belt guard: Totally enclosed metal
- Discharge lines: Copper tubing or stainless braided flex line
Motor and Electrical
- Horsepower: 30HP
- Phase: 3-phase
- Motor speed: 1725 RPM industrial
- Service factor: 15% minimum
- Motor starter: Factory-mounted magnetic motor starter (Z designation)
- Max working pressure: 175 PSI
Performance Specifications
- Motor output: 30 HP
- Electrical: 3-phase with factory-mounted magnetic starter
- Tank capacity: 240 gallons, horizontal
- Pump: C4 (Two-stage, V4)
- Pump RPM: 794
- Free air delivery (0 PSI): 128 CFM
- Delivery at 175 PSI: 105 CFM
- Max pressure: 175 PSI
- Dimensions (LxWxH): 90 x 39 x 70 inches
- Weight: 1,750 lbs
What's in the Box
- Castair I30324HC4Z-S compressor — fully assembled on 240-gallon horizontal tank
- Factory-mounted magnetic motor starter (Z designation)
- ASME safety valve (factory installed)
- Pressure switch with unloader
- Totally enclosed metal belt guard
- Copper discharge and unloader tubing (or stainless braided flex line)
- Owner's documentation
Aftercooler available as factory option (BGAC3M — for 20HP and up). Freight delivery: loading dock or forklift required. 3-phase electrical service and proper breaker sizing required — consult with your electrician before ordering.
The Full 20-30HP Industrial Lineup Compared
- I20324HC4Z-S: 20HP, 240gal, C4 pump, 519 RPM, 72 CFM @ 175 PSI, 1,700 lbs
- I25324HC4Z-S: 25HP, 240gal, C4 pump, 710 RPM, 90 CFM @ 175 PSI, 1,725 lbs
- I30324HC4Z-S (this unit): 30HP, 240gal, C4 pump, 794 RPM, 105 CFM @ 175 PSI, 1,750 lbs
The 30HP delivers 33 CFM more than the 20HP and 15 CFM more than the 25HP — substantial gains for applications that actually need that capacity. The weight difference across all three is only 50 lbs because the tank and pump assembly are the dominant cost. If your budget is within range of the 30HP, and your facility has the 3-phase service to support it, buying the extra capacity now avoids a forced upgrade later.
When Does a Shop Need This?
- Your continuous air demand is in the 90-105 CFM range at 175 PSI
- Large body shop: multiple spray guns active simultaneously plus general air tool demand
- Truck service facility: running multiple bays with large-format impact tools and air chisels
- Production environment: consistent high-volume air supply is a production constraint, not just a convenience
- You have 3-phase electrical service rated for a 30HP motor load
Consider rotary screw if:
- Your demand is 100% continuous duty (never stopping) — rotary screw compressors handle 100% duty cycle more efficiently than reciprocating units. The I30324HC4Z-S is rated for intermittent-to-heavy-duty use, not true 100% continuous operation.
Why Buy From Air Compressor Factory Direct?
A 30HP industrial compressor at this scale is a major facility decision. Since 2016, we have helped shops and production operations size, specify, and install equipment at this level. We can help you evaluate your electrical service capacity, confirm the footprint works in your space, and advise on aftercooler requirements for your application. There is no commission pressure here — we give you straight answers.
- Free shipping to commercial addresses in the lower 48 states (freight — loading dock or forklift required)
- Free tech support at 866-217-0063
- Full Castair manufacturer warranty
- Honest buying guidance — we will tell you if a rotary screw is a better fit for your duty cycle
- Authorized dealer with direct Castair factory support
Call 866-217-0063 for quick answers and help!
