Air Vents Bell & Gossett Water Vents Model 77, 78, 79
Overview
MODEL 77 PART NO. 401497
MODEL 78 PART NO. 401485
MODEL 79 PART NO. 401488

Overview
Product Features
Models 77, 78, 79
MODEL 77 PART NO. 401497
WATER VENT VALVE
- For efficient releasing of air in hydronic heating systems, such as baseboard radiators, convector radiators and small heating units
- 1⁄8″ NPT straight shank
- Maximum operating pressure 50 psig (3.5 bar)*
- Maximum temperature 240°F (116°C)
MODEL 78 PART NO. 401485
WATER MAIN VENT VALVE
- For use on high pressure hot or cold water or glycol mains and process applications with specific gravity
- greater than 0.7
- Cast brass body
- Tapped at top for 1⁄8″ NPT safety drain connection for discharging moisture
- Body unscrews for easy cleaning
- Built-in Check Valve
- 3⁄4″ NPT straight shank
- Maximum operating pressure 150 psig (10.3 bar)*
- Maximum hydrostatic pressure 450 psig (31.1 bar)
- Maximum temperature 250˚F (121˚C)
MODEL 79 PART NO. 401488
WATER MAIN VENT VALVE
- For use on hot or cold or glycol water mains and process applications with specific gravity greater than 0.7
- Tapped at top for 1⁄8″ NPT safety drain connection for discharging moisture
- Removable top
- Built-in Check Valve
- 1/2″ NPT female and 3⁄4″ NPT male straight shank
- Maximum operating pressure 75 psig (5.2 bar)*
- Maximum hydrostatic pressure 200 psig (13.8 bar)
- Maximum temperature 250˚F (121˚C)
*Drop away pressure (maximum pressure against which the vent can open).
Industries & Applications
Industries & Applications
Recommended Industries and Applications
Documentation & Tools
Documentation & Tools
Interactive Tools

Sizing Tools
- CAD Drawing Library for 2D and 3D dimensional drawings in many formats
- System Syzer
- System Syzer Psychrometry
- Steam-Pipe
- Steam-Loss
- Flash-Steam
- Condensate-Pipe

Steam + Water Pressure Reducing Values
Submittals