4 in. Ductile Iron Double Door Wafer Check Valve, UL/FM | 963004UL
4 in. Ductile Iron Double Door Wafer Check Valve, UL/FM | 963004UL
✓ In stock at our distribution warehouses — typically ships within 1–2 business days.
Freight item — ships LTL (Lower 48)- Flat-rate freight: $199 per order
- Orders $4,999+: quoted freight — priced for your dock, liftgate, and timeline
Buying several, or need a liftgate or jobsite delivery? Request an exact freight quote — usually answered the same business day.
The 4 in. ductile iron double door wafer check valve (part 963004UL) uses twin spring-loaded aluminum bronze doors for fast, non-slam closure and very low headloss. The compact wafer body installs between ASME B16.1 Class 125 / ASME B16.5 Class 150 flanges, in vertical or horizontal runs. UL 312/ULC listed with fusion-bonded epoxy coating inside and out — built for fire protection service.
Technical Specifications
| Manufacturer Part Number (MPN) | 963004UL |
| Nominal Size | 4 in. |
| Valve Type | Double door (dual plate) wafer check valve |
| Closure | Spring-loaded twin doors — fast, non-slam |
| Installation | Vertical or horizontal; fits between ASME B16.1 Class 125 / B16.5 Class 150 flanges |
| Seat | Resilient EPDM — tight sealing even at low differential pressure |
| Listing | UL 312 / ULC |
| Working Pressure | 300 psi @ 32–189°F (0–87°C) |
| Coating | Fusion-bonded epoxy, interior & exterior (AWWA C550) |
Dimensions
| Face-to-Face Length (L) | 64 mm / 2.52" |
| Body Outside Diameter | 162 mm / 6.38" |
Materials of Construction
| Body | Ductile Iron ASTM 65-45-12 |
| Doors (Discs) | Aluminum Bronze C954 |
| Spring | 304 Stainless Steel |
| Shaft | 420 Stainless Steel |
| Seat & Seal Ring | EPDM |
| Gaskets | PTFE |
| Hardware | Carbon Steel ASTM A325 |
Key Features
- Twin spring-loaded doors close before reverse flow develops — minimizes water hammer
- Wafer pattern: a fraction of the weight and face-to-face length of a swing check
- Excellent flow characteristics and low pressure loss at high flow rates
- Resilient seat seals tight even at low differential pressure
- Mounts vertical or horizontal
- UL 312/ULC listed; fusion-bonded epoxy coated to AWWA C550 for fire-line service
Other Sizes in This Series
Ductile Iron Double Door Wafer Check Valve. Jump to another size or add it straight to your cart:
| Size | Part # | Price | Cart |
| 4 in. UL/FM (this page) | 963004UL | $236.99 | — |
| 6 in. UL/FM | 963006UL | $513.99 | Add to cart |
For general water and HVAC service, the standard version of this size costs less.
Typical Applications
Fire protection mains, sprinkler and standpipe systems, and pump discharge lines requiring UL 312/ULC listed backflow prevention.
Cross-References & Interchange
Replacing another brand's 4 in. dual-plate wafer check? These interchange dimensionally with standard ASME Class 125/150 wafer checks — match nominal size and flange class, or send us your part number and we will confirm the fit.
Availability
In stock — ships direct from the manufacturer, typically 1–3 business days. Sizes in this series ship LTL freight.
Technical Resources
- Check Valve Types Explained (Swing, Spring, Wafer, Ball)
- Water Hammer: Causes & Fixes
- How to Choose the Right Valve
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