1/2 in. Brass Inline Check Valve, Viton
1/2 in. Brass Inline Check Valve, Viton
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The 1/2 in. brass inline check valve with Viton seal (part 944403V) provides compact, spring-loaded backflow prevention with a Viton (FKM) seal, which Midland specifies for fuels and hydrocarbons; rated to a maximum of 325°F and 125 psi steam. Rated 400 psi WOG with a low 1/2 psi cracking pressure, polyetherimide disc, and a patented disc guide that prevents side loading. Female NPT both ends. Made in Italy.
Technical Specifications
| Manufacturer Part Number (MPN) | 944403V |
| Nominal Size | 1/2 in. |
| Valve Type | Inline check valve (spring-loaded poppet), brass, Viton seal |
| End Connections | Female NPT × Female NPT |
| Pressure Rating | 400 psi WOG |
| Steam Rating | 125 psi saturated steam |
| Maximum Temperature | 325°F (Viton seal) |
| Cracking Pressure | 1/2 psi |
| Seat / Seal | Viton (FKM fluoroelastomer) — fuels, hydrocarbons, elevated temperature |
| Disc | Polyetherimide |
Materials of Construction
| Body & End Connection | Brass |
| Disc | Polyetherimide |
| Seat | Viton (FKM) |
| Spring | Stainless Steel |
Performance & Testing
- Viton (FKM) seal — specified by Midland for fuels and hydrocarbons, to 325°F
- Low 1/2 psi cracking pressure — opens with minimal upstream pressure
- Spring-loaded for fast seating; perfect seating at both high and low pressure
- Patented disc guide prevents side loading
- Compact, high-capacity design with a head-loss-minimizing flow profile
- Not lead-free — not for potable water service
Other Sizes in This Series
Brass Inline Check Valve, Viton (FKM) seal, Female NPT (3/8"–4"; 400 WOG through 2", 175 WOG above). Jump to another size or add it straight to your cart:
| Size | Part # |
| 3/8 in. | 944402V |
| 1/2 in. (this page) | 944403V |
| 3/4 in. | 944404V |
| 1 in. | 944405V |
| 1-1/4 in. | 944406V |
| 1-1/2 in. | 944407V |
| 2 in. | 944408V |
| 2-1/2 in. | 944409V |
| 3 in. | 944410V |
| 4 in. | 944411V |
Typical Applications
Backflow prevention on fuel, oil and hydrocarbon lines, including service above the 210°F limit of the Buna-N version (to 325°F). The 1/2 psi cracking pressure also suits low-head gravity and recirculation systems. Not for potable water supply (not lead-free).
Cross-References & Interchange
Replacing another brand's 1/2 in. brass inline check valve with FKM/Viton trim? Match nominal size, end connections, cracking pressure, and pressure rating for a direct fit — or send us your part number and we will confirm the interchange. Water, air, or general-purpose service? The 1/2 in. Buna-N version (944403) covers water, oils and general-purpose service up to 210°F. Need a stainless body? See the 1/2 in. 316 SS inline check valve (949403).
Technical Resources
Expert Guides for This Product
- Check Valve Orientation & Installation — flow direction and mounting rules
- Check Valve Sizing Guide — why line size isn't valve size
- Slamming & Water Hammer — causes and fixes
- Check Valve Leaking? — diagnose and fix it
- Check Valve Chattering — the sizing problem nobody checks
- Buna vs. Viton Seats — which elastomer fits your media