The Castair RS112 is a 1-1/2" NPT standard regulator rated at 250 maximum PSI and 500 CFM, sold without a gauge. The asterisk in the part number (*RS112) indicates this is the no-gauge configuration — the gauge port is present if you want to add one, but the unit ships without an installed gauge. At 500 CFM, this is a high-flow regulator designed for large industrial air supply headers, trunk lines, or main system pressure reduction — not for small shop drop-leg applications. If you need to regulate pressure on a main supply header feeding multiple stations at high volume, this is the regulator for that job.
Where This Regulator Belongs
The RS112 is at the top of Castair's standard regulator lineup. Put it in context:
- 1-1/2" body, 500 CFM: This flow capacity matches the output of large rotary screw or duplex piston compressors — machines in the 30–60+ HP range pushing 100–200+ CFM at the compressor. A 1-1/2" regulator on a header feeding six to twelve stations handles the aggregate flow without becoming the restriction in your system.
- 250 PSI maximum: Rated for full system pressure, not just regulated downstream pressure. You can install this directly on a 200 PSI rated compressor outlet header without concern about the regulator becoming a failure point under pressure spikes.
- No gauge (*) configuration: Appropriate where you have a gauge panel downstream, where you are monitoring pressure at the point of use rather than at the regulator, or where a gauge at this location would be inconvenient or redundant. If you want a gauge at the regulator, ask about the RS112 with gauge or add one to the gauge port.
Castair Regulator Lineup — Sizing Reference
- C-RE14 — 1/4" Mini, 150 PSI max, 38 CFM
- C-RS12 — 1/2" Std, 250 PSI max, 104 CFM
- C-RS34 — 3/4" Std, 250 PSI max, 162 CFM
- C-RS10 — 1" Std, 250 PSI max, 162 CFM
- RS114 (*) — 1-1/4" Std, 250 PSI max, 400 CFM — no gauge
- RS112 (*) — this unit — 1-1/2" Std, 250 PSI max, 500 CFM — no gauge
If you are sizing a regulator for a new installation, match the pipe size and CFM to your expected demand at that point in the system. The RS112 is appropriate for main headers in large facilities. A smaller 3/4" or 1" regulator is correct for drop-leg or individual station use.
Installation Notes
- Install with airflow direction per the regulator body arrow
- Mount with the adjustment knob accessible for pressure setting
- Castair recommends using a 5-micron particulate filter (FS112 or similar) upstream of any regulator to prevent debris from affecting the poppet and seat
- Gauge port location allows field installation of a gauge if needed after installation
Technical Specifications
- Part Number: RS112* (no-gauge configuration)
- Inlet/Outlet Size: 1-1/2" NPT
- Maximum Inlet Pressure: 250 PSI
- Flow Rating: 500 CFM
- Gauge: Not included (gauge port present)
- Manufacturer: Cast Air
Why Buy From OEM Diagnostic Tools?
Castair air system components shipped from our warehouse. Free shipping on qualifying orders. Free tech support at 866-217-0063. Full Castair manufacturer warranty. We can help you size the correct regulator for your system if you call with your CFM and pipe size requirements.
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