The Honeywell DU146-3/4A automatic bypass valve and differential pressure regulator controls the water flow in the heating circuit based on the differential pressure. It is used to ensure the minimum flow through the boiler and to limit the circulation pressure
in case the other heating circuits are closed.

The valve is installed if required by the boiler manufacturer or if a minimum flow must be maintained during boiler operation.

The use of automatic bypass valves is recommended in heating systems with a large number of thermostatic valves. When the thermostatic valves are open, the automatic bypass valve remains closed. However, as the thermostatic valves begin to close, the bypass valve opens to maintain the required water flow through the boiler.

The use of an automatic bypass valve reduces noise caused by water flow. It also helps reduce low-temperature corrosion of the boiler by increasing the return water temperature.

Features

• Maintains minimum water flow through the boiler
• Reduces noise in the heating system
• Prevents thermal corrosion of the boiler
• Easy differential pressure adjustment with control knob
• Well-readable numerical indicator