The Castair FS112 is a 1-1/2" NPT inline particulate filter rated for 390 CFM at up to 250 PSI. It sits in the compressed air line downstream of the compressor and removes solid contaminants — pipe scale, rust particles, compressor wear debris, and other particulates — down to 5 microns before the air reaches tools, spray guns, paint booths, or other pneumatic equipment. This is a high-flow filter for large shop and industrial air systems.
Where This Filter Goes in Your Air System
The FS112 is a main-line or point-of-use particulate filter for large air systems. A 1-1/2" NPT connection and 390 CFM capacity means this filter is sized for large rotary screw compressors or multi-compressor systems. It is not a filter for a small garage compressor — it is for industrial shops, production facilities, body shops with high-volume spray equipment, or any installation where 1-1/2" air mains are running.
The 16-ounce bowl holds collected contamination between drain intervals. Castair offers auto float drains (AFD3, 1/4" NPT; or AFD1, 1/8" NPT) that eliminate manual bowl draining — recommended for main-line filters where manual drain access is inconvenient.
Key Specifications
- Part Number: FS112
- Inlet/Outlet Size: 1-1/2" NPT (standard)
- Maximum PSI: 250 PSI
- Flow Capacity: 390 CFM
- Filtration Rating: 5 micron (particulate)
- Bowl Capacity: 16 oz
- Filter Element: EK602VB (shared with FS114)
FS112 vs. FS114 — Connection Size Is the Only Difference
These two filters share the same bowl size, flow rating, pressure rating, and element. The only difference is the inlet/outlet connection size:
- FS114 — 1-1/4" NPT, 250 PSI, 390 CFM, 16oz bowl
- FS112 — 1-1/2" NPT, 250 PSI, 390 CFM, 16oz bowl
Match the filter to your existing line size. Reducing from a 1-1/2" main to a 1-1/4" filter connection creates a flow restriction — use the FS112 on 1-1/2" mains.
Full Particulate Filter Lineup
- C-FM14 — 1/4" Mini, 150 PSI max, 38 CFM, 1.5oz bowl
- C-FS12 — 1/2" Std., 250 PSI, 140 CFM, 8.5oz bowl
- C-FS34 — 3/4" Std., 250 PSI, 160 CFM, 8.5oz bowl
- C-FS10 — 1" Std., 250 PSI, 180 CFM, 11oz bowl
- FS114 — 1-1/4" Std., 250 PSI, 390 CFM, 16oz bowl
- FS112 — 1-1/2" Std., 250 PSI, 390 CFM, 16oz bowl
Coalescing Filtration — When 5 Micron Is Not Enough
The FS112 removes solid particulates to 5 microns. It does not remove oil aerosols or water vapor. For spray painting, precision air tools, or any application where oil-free air is required, you need a coalescing filter (0.01 micron) downstream of the particulate filter. Castair's C-CF series coalescing filters cover 1/2" through 1" connections. Coalescing filters require a particulate pre-filter upstream — never run a coalescing filter directly on raw compressor output.
Auto Drain Options
- AFD3 — THB Bowl Auto Float Drain, 1/4" NPT
- AFD1 — Watts Bowl Auto Float Drain, 1/8" NPT
When Does a Shop Need This
- Main-line filtration on a high-volume shop air system with 1-1/2" mains
- Protection of spray booth equipment, precision tooling, or production air systems
- Replacing a failed or undersized main-line filter on a large rotary screw installation
- Any application where the line size is 1-1/2" and the system runs at or below 250 PSI
If your shop runs a smaller compressor with 1/2" or 3/4" air lines, you do not need the FS112 — you need a C-FS12 or C-FS34. The FS112 is sized for industrial-scale air systems.
Why Buy From OEM Diagnostic Tools?
OEM Diagnostic Tools has supplied professional shop equipment and components since 2016. We carry Castair air treatment equipment so shops can build and maintain properly filtered air systems. Free shipping on qualifying orders, free tech support at 866-217-0063, and full manufacturer warranty on every part. Call us if you need help selecting the right filter size or configuration for your system.
Call 866-217-0063 for quick answers and help!
