The Honeywell DU146 Automatic Bypass Valve (ABV) is designed to automatically regulate water flow within a heating system by controlling the bypass circuit between the flow and return pipework. It is typically installed on larger heating systems or branches of district heating systems to maintain consistent water circulation and system pressure. In line with Building Regulations, whenever a bypass is installed, an Automatic Bypass Valve must be fitted. The DU146 ensures optimal performance by allowing water to flow through the bypass only when necessary — such as when zone valves or thermostatic radiator valves begin to close, reducing system flow.

Improved System Efficiency

The DU146 helps improve heating system efficiency by maintaining proper circulation and preventing unnecessary energy use. By regulating pressure and flow automatically, it reduces system strain and ensures the boiler continues to operate under ideal conditions. The use of an Automatic Bypass Valve (ABV) is also recommended by the UK Government as best practice in the CHeSS (Central Heating System Specifications) guidance for central heating systems.

Key Features :

• Integral pressure indicator for quick and accurate setup

• Connection size: 3/4″

• Connection type: Threaded

• Connection gender: Female

• Maximum operating temperature: 110°C

• Wide differential pressure range: 0.05 – 0.5 bar

• Lockable set point adjustment for secure pressure settings

• Reduces system noise caused by pressure fluctuations

• Maintains consistent system pressure

• Ensures constant flow through the boiler or heating system branch

• Lockable set pressure prevents accidental adjustment

• 1-year manufacturer warranty