The Castair ROFD10 is the OEM spin-on oil filter for Castair rotary screw compressors equipped with the D10 air end. The D10 air end is used on Castair's 25–40 HP rotary screw models. This is an automotive-style spin-on filter element — easy to service without tools beyond a filter wrench, no housing to disassemble, and no element to handle. Castair designs its rotary screw maintenance components to be "off-the-shelf" and serviceable by shop personnel, not proprietary units requiring dealer service. The ROFD10 is the oil filtration side of that commitment.
Why the Oil Filter Matters in a Rotary Screw Compressor
In a rotary screw compressor, the lubricating oil does three jobs simultaneously: it lubricates the rotor bearings, it seals the rotor meshing clearances, and it cools the compressed air/oil mixture before separation. That oil circulates continuously through the air end, the separator, and the cooler. A clogged or bypassing oil filter lets particulate contamination circulate through bearing journals and rotor timing gears — the exact components that determine air end longevity. At 25–40 HP, air end replacement is a significant expense. The ROFD10 filter is not a cost to minimize; it is insurance on your air end investment.
Maintenance Interval and Compatibility
- Compatible air end: D10 (Castair designation for 25–40 HP rotary screw air ends)
- Filter type: Spin-on, automotive-style paper element
- Maintenance kit: Available as part of the MKD10 preventative maintenance kit (includes 2 air filters, 4 oil filters, 1 separator filter, 5 gallons synthetic Cast-Lube oil — 10% savings)
- Oil used with: GA4000 or FG4000 Castair synthetic rotary screw oil (1-year/4,000 hour rating)
- Service interval: Per Castair maintenance schedule — replace oil filter with each oil change
- Hour meter: Standard on all Castair rotary screw units for maintenance tracking
D10 Air End — Compressor Context
The D10 air end is found in Castair rotary screw compressors in the 25–40 HP range. These units run at 100% duty cycle, factory filled with 4,000-hour synthetic lubricant, and operate at 135, 150, or 175 PSI depending on the ordered pressure range. A typical 30 HP D10-equipped machine delivers approximately 130 CFM at 100 PSI. At that utilization level, filter maintenance is not optional — it is what keeps the air end running at the hours-stamped rating.
Maintenance Kit Option
If you are doing a full scheduled service on a D10 machine, consider the MKD10 preventative maintenance kit, which includes:
- 2 × RAFD10 air filter elements
- 4 × ROFD10 oil filters (this part)
- 1 × RSFD10-16-G30 separator filter element
- 5 gallons GA4000 synthetic Cast-Lube oil
- 10% savings vs. individual purchase
Technical Specifications
- Part Number: ROFD10
- Filter Type: Spin-on oil filter
- Compatible Air End: Castair D10
- Compatible Compressor HP: 25–40 HP rotary screw models
- Manufacturer: Cast Air
Why Buy From OEM Diagnostic Tools?
We supply genuine Castair OEM maintenance parts — not aftermarket substitutes. The ROFD10 is the correct filter for D10 air ends, and using the correct OEM filter matters for warranty compliance and air end longevity. Free shipping on qualifying orders. Free tech support at 866-217-0063. Full Castair manufacturer warranty.
Call 866-217-0063 for quick answers and help!
