Castair T25324HC3-S — 25HP Three-Phase Tandem Two-Stage Piston Air Compressor
The Castair T25324HC3-S is a 25-horsepower, three-phase tandem compressor running two cast-iron piston pumps on a 240-gallon horizontal tank. This is a serious air supply unit for large shops, production facilities, and industrial applications that demand high-volume, continuous air delivery. Two pumps, one motor, two-stage compression — built for shops where running out of air is not an option.
Specifications
| Horsepower | 25 HP |
| Phase | Three-phase (3-phase) |
| Pump Configuration | Tandem — 2 pumps, 1 motor |
| Compression | Two-stage |
| Tank | 240 gallon, horizontal |
| Pump RPM | 680 RPM |
| Dimensions (LxWxH) | 94 x 30 x 64 inches |
| Weight | 2,530 lbs |
| Model | T25324HC3 |
| Power | Electric |
Cast Iron Pumps
Castair tandem compressors use all cast-iron pump construction — not aluminum. Here is what is inside:
- Slow RPM operation (420-995 RPM range) for quiet running and long service life
- Tapered roller bearings at both ends of the crankshaft for superior support and less friction
- Precision steel connecting rods with automotive-type rod insert bearings at the crankshaft and bearings at the wrist pin
- Disc and spring valves for easy service, higher efficiency, and reliability
- 4-ring pistons for higher efficiency and less oil carry-over
- Centrifugal unloader for load-free startup every time
Tanks, Motors, and Controls
- Powder-coated ASME tank with channel supports on horizontal configuration
- ASME safety valves
- Metal belt guard, totally enclosed
- Copper discharge and unloader tube
- Heavy-duty 1725 RPM industrial motor with full 15% service factor
Included With Purchase
All Castair Tandem Series piston-driven compressors come with the Right From The Start Kit included.
About Castair
Family owned and operated since 1991. Cast iron pumps, oil-lubricated, slow RPM operation. These compressors are built for shops that need air they can count on, day after day. No shortcuts in materials or construction.
Shipping
Ships within two weeks of order placement. All orders receive a courtesy call to confirm conditions and application to ensure you are getting the right compressor.
Call 866-217-0063 for quick answers and help!
Frequently Asked Questions
What is a tandem compressor and how does it differ from a duplex unit?
A tandem compressor like the T25324HC3-S uses two pump heads driven by a single motor on one shared crankshaft — the pumps fire in sequence to smooth out pressure pulsation and reduce motor load spikes. A duplex runs two completely independent pump-motor sets that alternate or run simultaneously, giving you redundancy if one side goes down. The T25324HC3-S tandem design is more compact and costs less than a true duplex, but if the motor goes, both pump heads are offline at once.
What are the electrical requirements for the T25324HC3-S?
The T25324HC3-S is a 25 HP, 3-phase unit — it requires a 3-phase power supply, typically 208-230/460V at approximately 60-65 amps depending on your voltage configuration. You will need a dedicated circuit with a properly sized disconnect and overload protection sized to the motor FLA on the nameplate. This is not a single-phase machine; if you only have single-phase power at your facility, you will need a phase converter or a different model.
How much floor space does the T25324HC3-S require, and what clearances do I need?
The 240-gallon horizontal tank on the T25324HC3-S puts the footprint in the range of roughly 90" L x 30" W — confirm exact dimensions on the spec sheet, as tank configurations vary. Plan for a minimum of 24" clearance on all sides for airflow and service access to the belt guard, oil fill, and drain valve. Cast Air builds these with all cast iron pump components, so the unit is heavier than comparable steel-pump machines — verify your floor load rating before placement.
When does a 25 HP tandem setup make more sense than a standard single-pump 25 HP compressor?
The tandem configuration on the T25324HC3-S makes sense when you need high CFM output with reduced pump RPM — running two smaller pump heads instead of one large one keeps each pump in a lower, cooler RPM range, which extends valve and ring life in continuous-duty shops. If your application runs the compressor hard for extended periods (automotive, body shops, industrial lines), the tandem thermal management is a real operational advantage over a single oversized pump spinning faster. For light intermittent use, the added complexity is not necessary and a standard single-pump unit will do the job at lower cost.
What does routine maintenance look like on the T25324HC3-S, and how does Cast Air support it?
Routine maintenance on the T25324HC3-S follows standard cast iron pump intervals: oil changes every 500 hours or annually (whichever comes first), belt tension checks every 250 hours, air filter inspection monthly in dusty environments, and valve inspection annually under heavy use. Cast Air has been building all cast iron compressors out of Spicer, MN since 1991 — parts availability and longevity are strong points of the platform. If you have questions about maintenance schedules, parts, or whether this model is the right fit for your application, call us at 866-217-0063 — we are an authorized Cast Air dealer and can walk you through it.
