Automatic bypass control AVDA

  • Overview
  • Features and benefits
  • BIM drawings
  • Documents
  • Tender text
  • Contact

AVDA is self-acting differential pressure relief controller used for constant flow control or bypass control. Controller opens on rising differential pressure.

Features and benefits

The controller has a control valve, an actuator with one control diaphragm and handle for differential pressure setting.

For apartment block heating, district heating plant and central heating systems.

BIM drawings


Type Name Language Valid for Updated Download File type
Data sheet AVDA English Multiple 18 Mar, 2008 508.5 KB .pdf

Tender text

  • Bypass valve are to be selected on the required bypass flow rate and opening pressure loss 
  • The valves shall be capable of the required opening pressure within the published spring range 
  • The valves shall be installed with a partner valve to enable bypass flow measurement and flow limiting if necessary 
  • The partner valves shall be fixed orifice in DN15-50 and variable orifice in DN50 (high flow) to DN400
  • Installation 

    The valve shall be installed between flow and return in accordance with the flow direction shown on the valve casting 
  • The partner valve shall be on the return, just after the bypass valve, and within the impulse tube loop. If an installation schematic is required please contact your Danfoss representative 

Commissioning Method 

  • Set up the pump and system to deliver the conditions where bypassing should occur. This is the pump minimum flow or defined low flow rate 
  • Measure the flow rate on the partner valve. If you have an excess, reduce the flow rate on the partner valve. Record the flow rate in the commissioned condition 
  • Turn the spring setting mechanism on the valve until the calculated opening pressure loss is set 
  • If the valve is open, turn the mechanism until it is just closed. This point just between open and closed is the setpoint. Record the pressure setting as the actual opening pressure loss 
  • Open the system to design flow rate and operate as normal 
  • The valve will remain close in high load conditions and open in low flow conditions