The Castair I738VC1-S is a 7.5 HP, 3-phase industrial air compressor on an 80-gallon vertical ASME tank, with the C1 pump and a factory-mounted magnetic motor starter. The vertical tank measures 32x24x74 inches — a significantly smaller floor footprint than the equivalent horizontal tank at 64x20x48 inches. If your shop wall space is tight, the vertical configuration lets you push the compressor into a corner without giving up the 80-gallon reserve. Output is 32.4 CFM at 0 PSI and 24.8 CFM at 175 PSI from the C1 pump at 895 RPM. Shipping weight is 625 lbs — same as the horizontal version with the same pump.
Vertical vs. Horizontal Tank — The Real Tradeoff
Both tank orientations hold the same 80 gallons and operate at the same 175 PSI. The choice comes down to your shop's geometry:
- Vertical tank (this unit): 32x24 in. floor footprint, 74 in. tall — uses less floor space, good for fitting into corners or along walls with limited run. Requires adequate ceiling clearance (at least 7 feet clear above the tank)
- Horizontal tank (I738HC1-S): 64x20 in. floor footprint, 48 in. tall — lower profile, works under low ceilings or ductwork that a vertical won't clear. Takes more floor length
If ceiling height is not a constraint and floor space is, vertical is the better choice. If ceiling height is under 8 feet or you have ductwork running low, horizontal is safer.
Pump Features — Cast Iron C1 Two-Stage
- All cast iron construction: Cylinders, heads, and crankcase — cast iron throughout, not aluminum
- Slow 895 RPM operation: Belt-drive reduction from the 1,725 RPM motor keeps heat low and pump life long
- Tapered roller bearings at both crankshaft ends: Handles radial and thrust loads better than ball bearings under continuous service
- Precision steel connecting rods: Automotive-type rod insert bearings at crankshaft, needle bearings at wrist pin
- Disc and spring valves: Easy to service, reliable under sustained pressure cycling
- 4-ring pistons: Reduced oil carry-over into the discharge air
- Centrifugal unloader: No-load start on every cycle — head pressure releases before the motor cranks up
Tank and Frame Features
- 80-gallon vertical ASME-rated tank: Powder coated, four-leg base for stable floor installation — takes less floor space than a horizontal of the same capacity
- ASME safety valve: Factory installed, rated for working pressure
- Metal belt guard: Fully enclosed — not a plastic clip-on
- Copper discharge and unloader tube: Better heat dissipation than rubber or plastic lines
Motor and Electrical
- 1,725 RPM heavy-duty industrial motor: Full 15% service factor or higher — continuous duty rated
- Factory-mounted magnetic motor starter: 3-phase overload protection installed and wired at the factory — ready to connect to your electrical panel
- 3-phase operation: Smooth starts, lower peak current draw, longer motor life vs. single-phase
What's in the Box
- Castair I738VC1-S compressor assembly (C1 pump, motor, 80-gal vertical tank, belt drive, belt guard)
- Factory-mounted magnetic motor starter (3-phase, sized for 7.5HP)
- ASME safety valve (installed)
- Copper discharge and unloader tube (installed)
- Pressure switch (installed)
Available Configurations — 7.5HP 3-Phase Industrial Lineup
- I738HC1-S: 7.5HP, 3-phase, 80-gal horizontal, C1 pump, 895 RPM, 24.8 CFM@175PSI, 64x20x48 in., 625 lbs, magnetic starter included
- I738HC1: Same as above without factory-mounted magnetic starter
- I738HC2-S: 7.5HP, 3-phase, 80-gal horizontal, C2 pump, 585 RPM, 28.1 CFM@175PSI, 64x20x46 in., 730 lbs, magnetic starter included
- I738HC2: Same as above without factory-mounted magnetic starter
- I738VC1-S: 7.5HP, 3-phase, 80-gal vertical, C1 pump, 895 RPM, 24.8 CFM@175PSI, 32x24x74 in., 625 lbs, magnetic starter included
- I738VC1: Same as above without factory-mounted magnetic starter
- I738VC2-S: 7.5HP, 3-phase, 80-gal vertical, C2 pump, 585 RPM, 28.1 CFM@175PSI, 40x24x74 in., 730 lbs, magnetic starter included
- I738VC2: Same as above without factory-mounted magnetic starter
- I7312HC2-S: 7.5HP, 3-phase, 120-gal horizontal, C2 pump — maximum reserve for high-demand shops
When Does a Shop Need This vs. Stepping Up or Down
The I738VC1-S is the right call if: You have 3-phase power and want to conserve floor space. A vertical tank's footprint (32x24 in.) is significantly smaller than a horizontal (64x20 in.) — if your shop wall space is limited, the vertical tank lets you tuck the compressor into a corner while the height stays at 74 inches. Output is identical to the I738HC1-S: 24.8 CFM at 175 PSI from the same C1 pump and motor.
Choose horizontal (I738HC1-S) instead if ceiling height is the constraint rather than floor space — horizontal tanks are lower profile and fit under ductwork or low ceilings that a 74-inch vertical tank won't clear.
Step up to I738VC2-S for more CFM — the C2 pump delivers 28.1 CFM at 175 PSI if your shop's air demand exceeds what the C1 provides.
Technical Specifications
- Model: I738VC1-S
- Horsepower: 7.5 HP
- Phase: 3-phase
- Tank Capacity: 80 gallons
- Tank Type: Vertical, ASME-rated, powder coated
- Tank Dimensions: 32 x 24 x 74 in. (L x W x H)
- Shipping Weight: 625 lbs
- Pump Model: C1 (two-stage, cast iron, inline-2)
- Pump RPM: 895
- CFM @ 0 PSI: 32.4
- CFM @ 175 PSI: 24.8
- Max Working Pressure: 175 PSI
- Motor Speed: 1,725 RPM
- Starter: Factory-mounted magnetic motor starter included
- Magnetic Starter (208/230V): S72 with B36 heaters
- Magnetic Starter (460V): S74 with B22 heaters
- Discharge Tube: Copper
- Belt Guard: Metal, fully enclosed
Why Buy From Air Compressor Factory Direct?
We specialize in industrial and commercial air compressors and have been at it since 2016. When you call, you're talking to someone who knows the Castair lineup, can tell you whether the C1 or C2 pump fits your shop's CFM requirements, and can help you decide between horizontal and vertical tank configurations for your space. Free shipping, free technical support at 866-217-0063, full Castair manufacturer warranty. Call us before you buy if you have questions about which configuration is right for your shop.
Call 866-217-0063 for quick answers and help!
