The Castair VA100 is a 1" NPT Male x 18" metal flex hose for mid-size air compressors. This is the pump-to-tank discharge connection for Castair compressors with 1" NPT discharge ports — typically mid-range single-stage and smaller two-stage piston units. The 18-inch length gives the hose the flexibility to absorb pump vibration in all directions without kinking, while the 1" NPT male fittings thread directly into the pump outlet and tank check valve or manifold fitting.
The Purpose of This Component
A metal flex hose is the vibration break between the reciprocating pump and the stationary tank. Every stroke of a piston compressor introduces movement — up, down, and some rotational vibration from the crankshaft. Without a flex hose, that movement goes directly into the rigid fittings on each end. Tank fittings crack, check valves break at the body, and downstream manifold fittings work loose. A proper flex hose absorbs all of that before it reaches anything that can't flex.
The stainless braided construction also handles the thermal cycling that happens when a compressor runs to temperature and cools down. Repeated thermal expansion and contraction in a rigid system works fittings loose over time — the flex hose accommodates that movement.
Key Features
- 1" NPT Male Connection: Standard NPT thread sizing for mid-range Castair compressor pump outlets and tank fittings
- 18" Overall Length: Correct length for Castair compressor installations — enough flex without excessive hose length that could sag or kink
- Stainless Braided Flex Construction: Corrugated inner liner with stainless steel braid outer jacket for high-pressure compressed air service
- OEM Replacement Part: Castair factory-specification — direct replacement for the original equipment on Castair compressors with 1" NPT discharge
- Both-End Male NPT: Male threads on both ends for direct connection without reducing fittings or adapters
When to Replace
- Exterior braid shows corrosion, fraying, or cracking — once the braid is compromised, the hose can fail suddenly
- Kinks from installation — a kinked flex hose has stress concentrations that will eventually crack
- Weeping or active leak at either fitting end
- Hose feels rigid and has lost flexibility — metal flex hoses work-harden over time and lose their vibration-absorbing properties
- Compressor has been operated with a hard-piped connection and you're converting to a proper installation
Installation Notes
- Relieve all tank pressure before disconnecting any pump-to-tank lines
- Clean thread surfaces on both the pump outlet and tank fitting before installation
- Apply thread sealant to NPT threads — use a quality pipe thread compound or anaerobic sealant rated for compressed air
- Do not over-torque — 1" NPT fittings in aluminum pump bodies can crack if overtightened
- Route the hose with a gentle curve — do not pull it straight or allow it to kink at either fitting end
- After installation, run the compressor to full operating pressure and check both fittings for leaks with soapy water
Full Flex Hose Lineup
- VA075 ($59.29) — 3/4" NPT Male x 18"
- VA100 ($99.95) — 1" NPT Male x 18" (this part)
- VA050 ($46.59) — 1-1/2" NPT x 18"
- VA125 ($102.49) — 1-1/4" NPT x 18" — 25-40 HP rotary units
- VA150 ($111.80) — 1-1/2" NPT Male x 18"
- VA200 ($131.29) — 2" NPT Male x 18"
- VA100J36 ($203.28) — 1" JIC Female/Female x 36"
What's in the Box
- 1x Castair VA100 Metal Flex Hose — 1" NPT Male x 18"
Technical Specifications
- Part Number: VA100
- Manufacturer: Cast Air / Castair
- Connection Type: 1" NPT Male, both ends
- Length: 18 inches
- Category: Ball Valves / Flex Lines
- Price: $99.95
Pressure rating was not available from manufacturer data at time of writing. Confirm operating pressure compatibility before installation.
Why Buy From Air Compressor Factory Direct?
- Castair Parts Specialist: We stock the full flex hose lineup and can confirm the right size for your compressor
- Free Shipping: On qualifying orders to the contiguous US
- Free Tech Support: Call 866-217-0063 — size questions take about a minute to resolve
- OEM Quality: Castair factory-spec parts, not generic substitutes
- Full Manufacturer Warranty: Backed by Castair's standard product warranty
Call 866-217-0063 for quick answers and help!
