Castair I513HC2-S: 5HP Single-Phase Industrial Air Compressor — 80 Gallon Horizontal, C2 Pump, with Mounted Starter
The Castair I513HC2-S is a 5-horsepower, single-phase, 80-gallon horizontal industrial air compressor built on Castair's C2 cast iron pump with a factory-mounted magnetic motor starter. The defining feature of this unit compared to the C1-based models is the pump: the C2 runs at 420 RPM — well below the 767 RPM of the C1 — which translates to meaningfully quieter operation, less heat generated per hour of runtime, and longer pump service life between valve and ring service.
The performance output is the same as the C1 versions: 22.0 CFM free air, 17.5 CFM at 175 PSI. You are not buying more CFM when you choose the C2 — you are buying quieter operation and longer pump life. For shops where the compressor is in or near the work area, the noise difference is significant. For shops that run the compressor hard all day, the slower RPM means less wear accumulating per hour.
The C2 pump is a Two-stage, V4 cylinder design — four cylinders versus the C1's Inline 2. The V4 arrangement runs smoother and with less vibration than an inline twin, which is another reason the C2 is the premium choice at 5HP.
C2 Pump — Specifications
- Pump designation: C2 — Two-stage, V4 cylinder configuration
- Rated HP range: 7.5-10HP — this pump is running below its rated range at 5HP, which means additional longevity headroom
- Pump RPM: 420
- Flywheel: 19.0-2B
- Oil capacity: 2 quarts
- Construction: 100% cast iron — cylinders, heads, valve plates, crankcase
- 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 for efficiency and low oil carry-over
- Unloader: Centrifugal — loadless start-up on every cycle
Tank and Frame
- Tank capacity: 80 gallons, horizontal
- 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: 5HP
- Phase: Single-phase
- Motor speed: 1725 RPM industrial
- Service factor: 15% minimum
- Motor starter: Factory-mounted magnetic motor starter (-S designation)
- Max working pressure: 175 PSI
Performance Specifications
- Motor output: 5 HP
- Electrical: Single-phase with factory-mounted starter
- Tank capacity: 80 gallons, horizontal
- Pump: C2 (Two-stage, V4)
- Pump RPM: 420
- Free air delivery (0 PSI): 22.0 CFM
- Delivery at 175 PSI: 17.5 CFM
- Max pressure: 175 PSI
- Dimensions (LxWxH): 64 x 20 x 46 inches
- Weight: 700 lbs
What's in the Box
- Castair I513HC2-S compressor — fully assembled
- Factory-mounted magnetic motor starter (-S 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 (BGAC1M — 35 CFM, for 5-10HP models). Not included in base configuration.
C1 vs. C2 Pump at 5HP — Choosing the Right Configuration
- C1 pump (I513HC1-S): 767 RPM, Inline 2, lighter (600 lbs), lower cost — right choice when budget is the priority and noise level is acceptable
- C2 pump (I513HC2-S, this unit): 420 RPM, V4, heavier (700 lbs), premium — right choice when quieter operation or longer pump life matters more than initial cost
Both deliver 17.5 CFM at 175 PSI. The 420 RPM C2 runs about 45% slower than the 767 RPM C1 — at equal runtime hours, the C2 pump accumulates significantly less wear. If you are buying this compressor expecting to run it for 15-20 years, the C2 pump investment typically pays back in reduced maintenance and extended pump life.
When Does a Shop Need This?
- 1-2 technician shop on single-phase power that values quieter compressor operation
- Shop where the compressor is in or near the work area and noise level matters to technicians or customers
- High-runtime applications (8+ hours per day) where slower pump RPM meaningfully extends service intervals
- You want factory-mounted motor protection built into the unit
Why Buy From Air Compressor Factory Direct?
Since 2016, we have sold industrial air compressors to shops and facilities that need real equipment. The C2 pump choice at 5HP is a decision we talk through with customers regularly — it costs more upfront, runs quieter, and lasts longer. Whether that trade-off is right for your shop depends on your runtime and environment. Call us and we will help you decide.
- Free shipping to commercial addresses in the lower 48 states
- Free tech support at 866-217-0063
- Full Castair manufacturer warranty
- Honest buying guidance — C1 vs. C2 comparison included at no charge
- Authorized dealer with direct Castair factory support
Call 866-217-0063 for quick answers and help!
