Castair 1/2"x3/4" In-Tank Check Valve NPT Female Fitting Inlet / NPT Male Outlet CTB1234
The Castair CTB1234 is an asymmetric in-tank check valve — 1/2" NPT female inlet, 3/4" NPT male outlet. At $29.65, it's used when the compressor discharge port is 1/2" NPT but the tank bung or manifold connection is 3/4" NPT. One valve body handles the size transition from the smaller head connection to the larger tank fitting without additional reducers or bushings. Rated 500 PSIG and 400 degrees F with a 1/8" unloader port.
When You Need the CTB1234
- Compressor head has a 1/2" NPT male discharge port
- Tank has a 3/4" NPT female bung
- You need the valve to bridge these two different thread sizes in one body
- Common on mid-size compressors where the head discharge is smaller than the tank inlet, or where the original Castair build used this configuration
Technical Specifications
- Part Number: CTB1234
- Inlet Connection: 1/2" NPT Female (compressor side)
- Outlet Connection: 3/4" NPT Male (tank side)
- Pressure Rating: 500 PSIG
- Temperature Rating: 400 degrees F
- Unloader Port: 1/8" side port
- Price: $29.65
- Manufacturer: Castair (Spicer, Minnesota)
Full CTB Series Reference
- CTB3812 — 3/8" x 1/2", $21.18
- CTB1212 — 1/2" x 1/2", $20.33
- CTB1234 — 1/2" x 3/4" (this listing), $29.65
- CTB3434 — 3/4" x 3/4", $31.34
- CTB1010 — 1" x 1", $50.82
The CTD1234 (compression tube inlet, same outlet) performs the same function with 1/2" copper tubing inlet instead of NPT female thread.
Why Buy From Air Compressor Factory Direct?
Asymmetric check valves like the CTB1234 are easy to order incorrectly. We verify your configuration before shipping. Call with your compressor model or measure both connections and we'll confirm the correct part number before it ships.
- Free shipping on qualifying orders to the lower 48
- Free tech support — fitment confirmation before you order
- Full manufacturer warranty on all Castair products
Call 866-217-0063 for quick answers and help!
