Castair 1/2"x1/2" In-Tank Check Valve Compression Tube Fitting Inlet / NPT Outlet CTD1212
The Castair CTD1212 is a 1/2" x 1/2" in-tank check valve with compression tube fitting inlet and 1/2" NPT male outlet. At $21.18, it's the correct replacement when 1/2" copper discharge tubing runs from the compressor head directly into the check valve, which then threads into the 1/2" tank bung. The compression inlet grips the copper tube without soldering or flaring — insert the tube, tighten the nut, done. Rated 500 PSIG and 400 degrees F with a 1/8" unloader port.
Compression Inlet vs. NPT Inlet
- CTD series (this valve): Compression tube fitting inlet — 1/2" copper tubing inserts into the inlet and is clamped with a compression sleeve and nut. No threading on the tube end required.
- CTB series: NPT female inlet — a male NPT fitting or nipple threads into the valve. Used when discharge uses threaded pipe fittings rather than tubing.
CTD1212 is specified when 1/2" copper tubing runs from the compressor head discharge directly into the check valve. Many Castair compressor builds use this configuration.
Technical Specifications
- Part Number: CTD1212
- Inlet Connection: 1/2" Compression tube fitting
- Outlet Connection: 1/2" NPT Male
- Pressure Rating: 500 PSIG
- Temperature Rating: 400 degrees F
- Unloader Port: 1/8" side port
- Price: $21.18
- Manufacturer: Castair (Spicer, Minnesota)
Castair CTD Series Full Lineup
- CTD3838 — 3/8" comp x 3/8" NPT, $20.33
- CTD3812 — 3/8" comp x 1/2" NPT, $20.33
- CTD1212 — 1/2" comp x 1/2" NPT (this listing), $21.18
- CTD1238 — 1/2" comp x 3/8" comp, $25.41
- CTD1234 — 1/2" comp x 3/4" NPT, $29.65
- CTD3434 — 3/4" comp x 3/4" NPT, $29.65
- CTD3410 — 3/4" comp x 1" NPT, $46.59
Installation Note
Use with Castair's 1/2" compression nut and sleeve (CNS12) or standard 1/2" compression fittings rated for 500 PSI. Cut the copper tube square and deburr before inserting. Tighten the compression nut per fitting specs — overtightening can cut the tubing.
Why Buy From Air Compressor Factory Direct?
We stock the full Castair check valve line in both NPT and compression inlet styles. If you're replacing an existing valve and aren't sure which series you have, look at your current valve inlet — if tubing inserts into it, you have a CTD; if it has female threads, you have a CTB.
- Free shipping on qualifying orders to the lower 48
- Free tech support — identification and fitment help by phone
- Full manufacturer warranty on all Castair products
Call 866-217-0063 for quick answers and help!
