The Castair DP100M is the mounted version of the DP100 dryer pump kit — a complete dryer bypass assembly for Castair refrigerated dryers, configured so the dryer is physically mounted rather than floor-standing. Where the DP100 leaves the dryer placement to the installer, the DP100M includes the hardware to mount the dryer unit in a fixed position with the bypass plumbing integrated. This is the right choice when you want a clean, organized installation with the dryer secured rather than just plumbed in-line and resting on its own.
DP100 vs. DP100M — The Difference
Both kits serve the same function: they install a Castair refrigerated dryer with a proper 3-ball valve bypass, allowing dryer isolation for service without interrupting compressed air delivery. The distinction is mounting:
- DP100: Bypass plumbed, dryer not secured to a fixed mount — dryer sits wherever you position it (floor, existing bracket, etc.)
- DP100M (this unit): Bypass plumbed and dryer is mounted in a fixed position via the included mounting hardware — cleaner installation, dryer doesn't shift or vibrate loose over time
For permanent shop installations where the dryer location won't change, the DP100M is the better choice. For temporary setups or installations where the exact position may need to be adjusted later, the DP100 gives you more flexibility.
Compatible Dryer Models
DP100M is designed for Castair refrigerated dryers in the larger size range (RD71-15K and up). These dryers are too large and heavy to mount on the compressor itself:
- RD71-15K: 71 CFM @ 37°F, 1" NPT, 115V/1ph, 7.5A, 110 lbs, 11.8x23.7x22.8"
- RD113-60K: 107 CFM @ 37°F, 1" NPT, 115V/1ph, 9.0A, 119 lbs, 11.4x30.5x24.5"
- RD161-37K: 161 CFM @ 37°F, 1.5" NPT, 115V/1ph, 11.4A, 137 lbs, 11.4x33.7x24.5"
What's Included with DP100M
- 3-ball valve bypass assembly
- Dryer mounting hardware
- Plumbing fittings for dryer connection
Note: Exact hardware list, dimensions, and weight are not published in Castair's public data. Contact us to confirm what's included before ordering.
About Castair Refrigerated Dryers
The dryers used with the DP100M are Castair's industrial refrigerated dryers. Key specifications:
- Target dew point: 37°F at rated conditions (100°F inlet, 100°F ambient, 100 psi)
- Capacity derating: At 150°F inlet temperature, capacity is 55% of the rated CFM figure
- Refrigerant: R134a and R407c
- Stainless steel heat exchanger
- Automatic condensate drain — only activates when moisture is present
- Max inlet pressure: 232 psig
- Power: 115V, 1-phase, 60Hz
- UL listed
Why Buy From Air Compressor Factory Direct?
- Specialist since 2016 — we stock Castair equipment and accessories
- Free shipping on qualifying orders
- Free tech support at 866-217-0063 — we'll help you plan your dryer installation
- Full manufacturer warranty on all Castair products
- Honest guidance — if the DP100 (unmounted) better suits your setup, we'll tell you
Call 866-217-0063 for quick answers and help!
