The Honeywell DU146-3/4A automatic bypass and differential pressure valve is used to maintain constant differential pressure in a heating system. It reduces flow noise in a system, particularly as thermostatic radiator valves are closing.

The valve is installed if required by the boiler manufacturer or if a minimum flow rate 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 overflow valve remains closed. However, as soon as the thermostatic valves begin to close, the pressure relief valve opens to maintain the required water flow through the boiler.

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

Features

• Maintains minimum water flow through the boiler
• Minimises flow noise
• Hinders boiler corrosion
• Differential pressure finely adjustable
• Setting value is in meters water column