Castair 1/2"x1/2" In-Tank Check Valve NPT Female Fitting Inlet / NPT Male Outlet CTB1212
The Castair CTB1212 is a 1/2" x 1/2" in-tank check valve with NPT female inlet and NPT male outlet. At $20.33, it's the correct factory replacement for small to mid-size commercial reciprocating compressors with 1/2" NPT discharge and tank connections. Rated to 500 PSIG and 400 degrees F with a 1/8" side port for unloader connection, it handles everything a standard shop compressor in the 1.5-5 HP range delivers.
What This Valve Does
- Holds tank pressure: Closes when head pressure drops below tank pressure, preventing air from back-flowing from tank through the compressor
- Unloader connection: The 1/8" side port connects to your pressure switch unloader valve to bleed head pressure at shutdown
- Common failure sign: Short-cycling compressor, or tank slowly losing pressure when the compressor is off, often traces to a failed check valve
Technical Specifications
- Part Number: CTB1212
- Inlet Connection: 1/2" NPT Female
- Outlet Connection: 1/2" NPT Male
- Pressure Rating: 500 PSIG
- Temperature Rating: 400 degrees F
- Unloader Port: 1/8" side port
- Price: $20.33
- Manufacturer: Castair (Spicer, Minnesota)
CTB vs. CTD for 1/2" Systems
- CTB1212 (this listing): NPT female inlet — use when the discharge connection uses threaded pipe fittings and nipples into the valve
- CTD1212: Compression tube fitting inlet — use when 1/2" copper tubing inserts directly into the check valve via compression fitting
Both are the same size and similar price. The inlet connection style is the only difference.
Full CTB Series Reference
- CTB3812 — 3/8" x 1/2", $21.18
- CTB1212 — 1/2" x 1/2" (this listing), $20.33
- CTB1234 — 1/2" x 3/4", $29.65
- CTB3434 — 3/4" x 3/4", $31.34
- CTB1010 — 1" x 1", $50.82
Why Buy From Air Compressor Factory Direct?
We stock the full Castair check valve line. If you're not sure whether you need the NPT female (CTB) or compression (CTD) inlet version, call us — we can confirm based on your existing discharge assembly.
- Free shipping on qualifying orders to the lower 48
- Free tech support — fitment help by phone
- Full manufacturer warranty on all Castair products
Call 866-217-0063 for quick answers and help!
