Danfoss AB-QM was the first of its kind control valve for HVAC heating and cooling applications. It is a control valve with automatic flow limitation and built-in differential pressure control functioning over the control valve. The result of this concept is a high performing control valve with a – still - unique valve authority of 100%. The design flow can easily be set to the needed amount by using a 20-100% scale. Simply setting the design flow replaces traditional commissioning processes, gives a much more accurate control and avoids Kv calculations for system designers.
Features and benefits
Efficient energy transfer and minimal pumping costs since there are no overflows at partial loads because of the exact pressure independent flow limitation.
Smaller pump investments and lower energy consumption as the pump head needed is lower than in the traditional setup. With the built in test plugs it is easy to troubleshoot and find the optimal setpoint for the pump.
Reduced movements of the actuator since the built-in differential pressure controller ensure the pressure fluctuations do not influence the room temperature.
Achieving a stable temperature in a room leading to a lower average temperature at the same comfort level.
Minimal flow complains, as the valve performs as designed.
Minimal blockage complains, as the membrane design makes AB-QM less susceptible to blockage than a cartridge type constriction.
Trouble-free segmentation of the building project. When sections of a project are finished they can normally not be handed over to the customer with a fully functional HVAC installation. However the AB-QM with a Danfoss actuator will automatically control the flow, even when other parts of the installation are still unfinished. It’s not needed to adjust the AB-QM after finalisation of the project.
Commissioning costs, the costs are close to zero because of a convenient setting procedure without the need for flow charts, calculations or measuring equipment. The AB-QM valves can be set to a precise design value even when the system is up and running.
Halved mounting costs as the AB-QM valve covers two functions, Balancing & Control.
- All 2-port control valves shall PICV type
- The PICV shall be full authority at all flow settings
- The valve should be capable of achieving all flow rates for the system design within its published setting range
- Modulating valve/actuator combinations shall be capable of equal percentage control in all sizes. Linear only is not acceptable
- Actuator selected as per required (or specified) BMS protocol
- The actuator shall be provided by the same manufacturer as the valve
- Each valve will come with test points for flow verification
- The setting mechanism will be a direct stroke setting type. Full stroke is not permitted due to lack of control authority
- The manufacturer of PICV shall provide independent tests demonstrating flow and control performance of the valve
Specified Valve: Danfoss AB-QM Specified Actuator: Danfoss Actuator range. Selection as per the required control signal.
Experts within Heating
Greg Tracy has been working in the HVAC industry for the last 15 years. Having worked at Danfoss for 10 years, Greg managed the Danfoss Underfloor Heating division in the UK. For the last 5 years he has been working and managing the Danfoss HVAC division with consultants and contractors on some of Londons most prestigious Commercial buildings.
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