The Castair RD71-15K is a refrigerated compressed air dryer rated at 71 CFM at a 37°F pressure dew point. It is built for mid-size shops running 15–20 HP compressors — production environments, multi-bay auto shops, large body shops, or fabrication operations where air demand regularly pushes past 60 CFM. Unlike the smaller RD25 and RD59 units, the RD71-15K uses 1" NPT connections, matching the larger plumbing typical of 15–20 HP installations.
Same proven Castair refrigeration design: R134a or R407c refrigerant, stainless steel heat exchanger, automatic demand drain, and a simple dew point indicator. No computer boards to fail, no programming, no proprietary control systems to troubleshoot at 7 AM when you are trying to get the shop running.
How It Works
- Refrigeration cycle: Compressed air flows through the stainless steel dual-function heat exchanger. Freon cools the air to a 37°F dew point, condensing moisture into liquid that is ejected by the automatic drain.
- Dual-function heat exchanger: Pre-cools incoming hot air using outgoing cold air — improves efficiency and extends refrigerant component life.
- Automatic demand drain: Only activates when condensate is present. Conserves compressed air versus timer-based drains.
- Quick connect refrigerant port: Allows refrigerant recharge without full disassembly — a practical service feature for older units.
Key Features
- Rated capacity: 71 CFM at 37°F dew point (86 CFM at 50°F dew point)
- Connections: 1" NPT inlet and outlet — sized for 15–20 HP compressor installations
- Power: 115V / 1-phase / 60Hz with 9-foot three-prong power cord
- Current draw: 7.5 amps
- Refrigerant: R134a / R407c (environmentally compliant)
- Maximum inlet pressure: 232 PSIG
- Heat exchanger: Stainless steel for long service life
- Dew point indicator: Simple visual indicator, no computer logic required
- Certifications: UL listed
- Weight: 110 lbs
- Dimensions (W×D×H): 11.8" × 23.7" × 22.8"
What's in the Box
- Castair RD71-15K refrigerated air dryer unit
- 9-foot three-prong 115V power cord (pre-installed)
- Refrigerant pre-charged at the factory (R134a/R407c)
- 1" NPT inlet/outlet connections
Note: A properly sized pre-filter is required for warranty. Use a Castair 1" particulate filter (C-FS10) upstream of the dryer. For compressors without an aftercooler, install one before the dryer to maintain full rated capacity. The Castair #DP100 bypass kit is available for this unit — plumbed rather than mounted directly on the compressor.
Available Configurations / Upgrade Path
Where the RD71-15K fits in the Castair refrigerated dryer lineup:
- RD25-6K — 25 CFM @ 37°F: 3/4" NPT, 57 lbs. For 5–7.5 HP compressors.
- RD59-11K — 59 CFM @ 37°F: 3/4" NPT, 73 lbs. For 10–15 HP compressors.
- RD71-15K — 71 CFM @ 37°F: This unit. 1" NPT, 110 lbs. For 15–20 HP compressors.
- RD113-60K — 107 CFM @ 37°F: 1" NPT, 119 lbs. For 20–25 HP compressors.
- RD161-37K — 161 CFM @ 37°F: 1-1/2" NPT, 137 lbs. For high-demand shops.
- Larger custom sizes — call for pricing.
When Does a Shop Need This vs. Stepping Up or Down
The RD71-15K is the right dryer if:
- Your compressor is 15–20 HP and produces 60–71 CFM peak demand
- Your air supply lines are already 1" — the larger connection size eliminates the reducer hardware required with 3/4" dryers
- You run a multi-bay auto shop, a dedicated paint booth plus tool air, or a manufacturing operation with multiple pneumatic stations
- You have 115V single-phase power (three-phase not required)
Step up to the RD113-60K if:
- Your compressor produces more than 71 CFM peak demand
- You are running back-to-back production cycles or multiple spray guns simultaneously at full CFM draw
Capacity note: Ratings are based on 100°F inlet air, 100°F ambient, 100 PSI. At 150°F inlet air temperature, effective capacity drops to approximately 39 CFM. An aftercooler between the compressor and dryer is strongly recommended if your compressor runs without one.
Technical Specifications
- Model: RD71-15K
- CFM @ 37°F dew point: 71
- CFM @ 50°F dew point: 86
- Inlet/Outlet Connection: 1" NPT
- Voltage / Phase / Hz: 115V / 1-phase / 60Hz
- Amperage: 7.5 A
- Refrigerant: R134a / R407c
- Maximum Inlet Pressure: 232 PSIG
- Pressure Dew Point: 37°F
- Heat Exchanger: Stainless steel, dual-function single body
- Drain Type: Automatic, demand-based
- Power Cord: 9 ft, three-prong 115V plug
- Weight: 110 lbs
- Dimensions (W×D×H): 11.8" × 23.7" × 22.8"
- Certifications: UL Listed
Why Buy From Air Compressor Factory Direct?
We specialize in compressed air equipment and have since 2016. We stock Castair refrigerated dryers and can help you confirm the right model for your compressor output — including whether you need an aftercooler upstream to maintain full rated capacity. Free shipping on qualifying orders, free pre-sale technical support, and the full Castair manufacturer warranty.
Call 866-217-0063 for quick answers and help!
