Hoffman Specialty 79 Water Main Vent Valve, 401488
Product Images
Images are for representation only and may differ from the actual product.
Product Images
Images are for representation only and may differ from the actual product.
Hoffman Specialty Model 79 water main vent valve, part 401488, releases air from compatible hot-water, cold-water and glycol-water mains. The straight inlet provides both 1/2-inch female NPT and 3/4-inch male NPT connection options.
A built-in check valve helps prevent air from entering when system pressure falls. The removable top supports service access, and the 1/8-inch NPT outlet allows a safety drain connection where discharged moisture needs to be directed away.
| Feature | Benefit |
|---|---|
| Built-in check valve | Helps prevent outside air from returning as system pressure drops. |
| Dual-size inlet | Offers either 1/2-inch female or 3/4-inch male NPT connection. |
| Removable top | Provides access for vent maintenance. |
| Threaded discharge | Accepts a piped drain for managing moisture discharge. |
| Specification | Detail |
|---|---|
| Manufacturer / model | Hoffman Specialty 79 |
| Manufacturer part number | 401488 |
| Inlet | 1/2-inch female NPT /3/4-inch male NPT, straight shank |
| Outlet | 1/8-inch NPT safety drain connection |
| Maximum operating pressure | 75 psig (maximum pressure against which the vent can open) |
| Maximum hydrostatic pressure | 200 psig; not the operating venting-pressure rating |
| Maximum temperature | 250°F |
| Fluid selection | Hot or cold water, or glycol-water applications with specific gravity greater than 0.7 |
Select this vent by the actual system pressure and fluid, not connection size alone. The 200 psig hydrostatic limit does not increase the 75 psig operating limit.
| Check | What to confirm |
|---|---|
| Replacement identity | Match Model 79 and part 401488; do not substitute the different Model 78 on size alone. |
| Connection arrangement | Identify which inlet thread your system uses and whether a drain line is required. |
| Service conditions | Confirm pressure, maximum temperature and fluid specific gravity. |
| Installation and maintenance | Follow the manufacturer instructions and provide access to the removable top. Verify the suitability of the vent location and drainage arrangement. |
Need help selecting the correct water main vent? Contact UnitedBuilt through online chat, email parts@unitedbuilt.com, or call 602-253-7750 with your existing part number, connection size and operating pressure.