Honeywell V4943B1019U Diaphragm Gas Valve 1 Inch Npt

Product Description

The HONEYWELL V4943B1019U is a single-stage, pressure-regulating diaphragm gas valve with a slow-opening design. It controls gas flow in heating equipment by using a diaphragm mechanism to regulate outlet pressure and provide a controlled, gradual valve opening on each call for heat. The 1-inch NPT pipe connection and 0.5 psi maximum pressure rating make it suited for a range of commercial and residential gas-fired heating applications. Licensed gas technicians and HVAC service professionals typically handle installation and commissioning of this valve.

This valve is used on boilers, unit heaters, duct furnaces, makeup air units, and rooftop heaters. Its single-stage pressure regulation simplifies system design where two-stage firing is not required. The slow-opening characteristic reduces pressure surges at ignition, which is important in larger heating appliances where abrupt gas delivery can cause ignition problems or burner instability. It fits applications where a 1-inch NPT gas train connection is specified.

Key Features

• Single-stage pressure regulation for consistent outlet gas pressure
• Slow-opening operation reduces ignition pressure surges
• 1-inch NPT pipe connection for direct in-line gas train installation
• 0.5 psi maximum inlet pressure rating
• Diaphragm design provides reliable, repeatable pressure control
• Suitable for boilers, unit heaters, duct furnaces, makeup air, and rooftop heaters

Compatibility

The V4943B1019U is part of the V4943/8943B, C, and N valve series and is designed for use on boilers, unit heaters, duct furnaces, makeup air units, and rooftop heaters requiring a single-stage pressure-regulating gas valve with a 1-inch NPT connection.

Installation Notes

Installation must be performed by a licensed gas technician or qualified HVAC professional in accordance with local codes and the appliance manufacturer's instructions. Shut off the main gas supply and verify zero pressure at the valve before beginning any work. The valve body must be installed with the correct gas flow direction as indicated by the arrow on the valve body, and all NPT connections must be leak-tested with an approved gas leak detection solution after installation. Consult applicable codes such as the IFGC and local jurisdictional requirements before placing the appliance back in service.

Technical Specifications

• Pipe Size: 1 inch NPT
• Maximum Inlet Pressure: 0.5 psi
• Valve Action: Slow Opening
• Regulation Type: Single Stage Pressure Regulating
• Valve Type: Diaphragm Gas Valve

Standard Information

• Brand: HONEYWELL
• Manufacturer Part Number: V4943B1019U