Castair 3/4"x3/4" In-Tank Check Valve NPT Female Fitting Inlet / NPT Male Outlet CTB3434
The Castair CTB3434 is a 3/4" x 3/4" in-tank check valve with NPT female inlet and NPT male outlet. At $31.34, it's the correct factory replacement for mid-to-large commercial reciprocating compressors running 3/4" NPT connections in the discharge circuit. Rated to 500 PSIG and 400 degrees F with a 1/8" unloader port. If your compressor head has a 3/4" male discharge port and your tank has a 3/4" bung, this is the check valve you need.
Technical Specifications
- Part Number: CTB3434
- Inlet Connection: 3/4" NPT Female
- Outlet Connection: 3/4" NPT Male
- Pressure Rating: 500 PSIG
- Temperature Rating: 400 degrees F
- Unloader Port: 1/8" side port
- Price: $31.34
- Manufacturer: Castair (Spicer, Minnesota)
What This Valve Does
- Prevents backflow: Closes when the compressor unloads, holding tank pressure without loss through the compressor head
- Unloader function: The 1/8" side port connects to the pressure switch unloader to bleed head pressure at each shutdown cycle
- Diagnostic value: Short-cycling compressor or slow tank pressure loss when off often traces directly to a failed check valve — this is the first component to inspect
CTB3434 vs. CTD3434
- CTB3434 (this listing): 3/4" NPT female inlet — threaded pipe connection. Use when discharge uses pipe fittings and nipples.
- CTD3434: 3/4" compression tube fitting inlet. Use when 3/4" copper discharge tubing inserts directly into the valve.
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", $29.65
- CTB3434 — 3/4" x 3/4" (this listing), $31.34
- CTB1010 — 1" x 1", $50.82
- CTB114114 — 1-1/4" x 1-1/4" (call for price)
- CTB112112 — 1-1/2" x 1-1/2" (call for price)
Why Buy From Air Compressor Factory Direct?
We stock the full Castair check valve line in all sizes and inlet styles. Call with your compressor model or discharge connection details and we'll confirm the correct valve before it ships.
- Free shipping on qualifying orders to the lower 48
- Free tech support — fitment verification by phone
- Full manufacturer warranty on all Castair products
Call 866-217-0063 for quick answers and help!
