Castair 1"x1" In-Tank Check Valve NPT Female Fitting Inlet / NPT Male Outlet CTB1010
The Castair CTB1010 is a heavy-duty in-tank check valve with 1" NPT female inlet and 1" NPT male outlet. Rated to 500 PSIG and 400 degrees F with a 1/8" side port for unloader connection, this valve is the correct factory replacement for large-bore Castair compressor systems with 1" tank connections. The NPT female inlet threads onto the compressor discharge; the NPT male outlet threads into the 1" tank bung. At $50.82, it's a precision replacement that matches the configuration your compressor was built with.
What an In-Tank Check Valve Does
- One-way flow: Allows compressed air to flow from the compressor into the tank during the compression stroke, prevents air from flowing back through the discharge when the compressor unloads or stops
- Unloader port: The 1/8" side port connects to the pressure switch unloader line, allowing head pressure to bleed off at shutdown so the motor restarts unloaded
- Tank protection: Holds compressed air in the tank when the compressor is off — without this valve, the tank back-bleeds through the compressor
- Failure symptom: Short-cycling, frequent restarts, or slow tank pressure loss when the compressor is off are common signs of a failed check valve
Technical Specifications
- Part Number: CTB1010
- Inlet Connection: 1" NPT Female
- Outlet Connection: 1" NPT Male
- Pressure Rating: 500 PSIG
- Temperature Rating: 400 degrees F
- Unloader Port: 1/8" side port
- Price: $50.82
- Manufacturer: Castair (Spicer, Minnesota)
Castair CTB Series — Full NPT Female Inlet Lineup
- 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", $31.34
- CTB1010 — 1" x 1" (this listing), $50.82
- CTB114114 — 1-1/4" x 1-1/4" (call for pricing)
- CTB112112 — 1-1/2" x 1-1/2" (call for pricing)
When You Need CTB1010 vs. Smaller Sizes
- CTB1010: Large reciprocating compressors, typically 7.5 HP and above, with 1" NPT discharge ports and 1" tank bungs
- CTB3434: Mid-size commercial compressors, typically 3-7.5 HP, with 3/4" connections
- CTB1212 / CTB1234: Smaller commercial units, 1.5-5 HP, with 1/2" discharge connections
CTB vs. CTD Series
- CTB (this series): NPT female inlet — threaded pipe connection on the discharge side
- CTD series: Compression tube fitting inlet — copper tubing inserts and is clamped with compression fitting, no threading
Why Buy From Air Compressor Factory Direct?
We stock the full Castair check valve line. Call with your compressor model or thread sizes and we'll confirm whether CTB1010 is the right valve for your installation.
- Free shipping on qualifying orders to the lower 48
- Free tech support — fitment confirmation by phone before you order
- Full manufacturer warranty on all Castair products
Call 866-217-0063 for quick answers and help!
