The Honeywell Home DU144 22mm Straight Bypass Valve automatically regulates circulation between the flow and return pipework in hydronic heating systems, maintaining the minimum required flow to the boiler. This prevents pressure spikes, reduces noise from high water velocity, and supports efficient boiler operation. The valve is especially useful in systems with multiple thermostatic radiator valves.

Key Features

• Supports healthier boiler operation by helping reduce corrosion linked to low return temperatures and condensation
• Minimises pressure fluctuations and system noise by opening only when required to relieve excess circulation
• Suitable for heating systems where a bypass circuit is required to comply with boiler manufacturer instructions
• Differential pressure can be finely adjusted using the built-in indicator scale for precise system balancing
• 22mm compression connection for straightforward installation between flow and return lines
• Helps maintain the correct boiler flow rate by automatically opening as TRVs begin to close
• Presetting is covered by a protection cap

Technical Information

• Maximum Operating Temperature: 110°C
• Differential Pressure Range: 0.1-0.6 bar
• Maximum Operating Pressure: 10 bar
• Housing Material: Brass
• Factory Preset: 0.2 bar
• Connection Size: 3/4"
• pH Value: 8

Installation Instructions

• Fit between the flow and return pipework to ensure the correct minimum flow is maintained
• Recommended to install shut-off valves on either side for easier servicing