The Castair FS114 is a 1-1/4" NPT inline particulate filter rated for 390 CFM at up to 250 PSI. It removes solid contaminants — rust scale, pipe debris, compressor particulates — down to 5 microns from the compressed air stream before the air reaches tools, spray equipment, or process air applications. The 16-ounce bowl holds collected contamination between drain cycles. This is a high-flow filter sized for industrial and large commercial shop air systems.
Where This Filter Fits
A 1-1/4" NPT connection and 390 CFM flow capacity puts the FS114 in large shop and light industrial territory. Think 30-75 HP rotary screw compressors, large multi-drop shop air systems, or production facilities with high air consumption. If your main air distribution line is 1-1/4", the FS114 is the correct main-line particulate filter.
The 16oz bowl capacity is appropriate for this flow rate — on a high-volume system, contaminants accumulate faster than on small shop filters. Castair offers auto float drain valves (AFD3 with 1/4" NPT, AFD1 with 1/8" NPT) that eliminate manual bowl draining on main-line installations.
Key Specifications
- Part Number: FS114
- Inlet/Outlet Size: 1-1/4" NPT (standard)
- Maximum PSI: 250 PSI
- Flow Capacity: 390 CFM
- Filtration Rating: 5 micron (particulate)
- Bowl Capacity: 16 oz
- Filter Element: EK602VB (shared with FS112)
FS114 vs. FS112 — Connection Size Is the Only Difference
These two filters are identical in performance — same bowl size, same 390 CFM flow rating, same 5-micron element, same 250 PSI rating. The only difference is the connection size:
- FS114 — 1-1/4" NPT connection (this model)
- FS112 — 1-1/2" NPT connection
Use the FS114 on systems with 1-1/4" mains. Do not reduce the connection size from a 1-1/2" main to a 1-1/4" filter — that creates a flow restriction at the filter body.
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 (this model)
- FS112 — 1-1/2" Std., 250 PSI, 390 CFM, 16oz bowl
When to Add Coalescing Filtration
The FS114 removes particulates to 5 microns. It does not remove oil aerosols or water vapor. For spray painting, instrument air, or oil-sensitive applications, you need a Castair coalescing filter (C-CF series, 0.01 micron) downstream of the FS114. Always run a particulate filter upstream of a coalescing filter — the coalescing element is not designed for heavy solid contamination loads and will plug rapidly without the pre-filter in place.
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 particulate filtration on a large shop air system with 1-1/4" mains
- Pre-filter upstream of a coalescing filter for oil-free air applications
- Replacement for a failed or undersized filter on a high-flow air system
- Industrial or production air systems where solid contaminants cannot reach the process
Why Buy From OEM Diagnostic Tools?
OEM Diagnostic Tools has supplied professional shop equipment and components since 2016. We carry Castair air treatment products so shops can maintain properly filtered air systems. Free shipping on qualifying orders, free tech support at 866-217-0063, and full manufacturer warranty. Call us if you need help selecting the correct filter for your system's connection size and CFM requirements.
Call 866-217-0063 for quick answers and help!
