The automatic balancing valve is a constant flow rate device that contains a variable orifice to govern water flow. Since it is a variable orifice, it cannot be described with a Cv or a pressure drop at a given flow for piping system design purposes. Conversely, the designer may assume a constant flow rate over the pressure differential range of 2–5 to 80 psid as one uses constant pressure in system design.
Automatic flow kits are an excellent choice in providing protection through a constant, accurate flow to the equipment flow balancing choices have taken the guesswork out of system balancing. From the most economical means of system balancing, to an automated flow system, Trane’s flow kits support a variety of water-source heat pump applications.
For automatic balancing of a water-source heat pump, the fluid controls automatic hose kit provides a constant flow rate over the pressure differential range of differential operating pressure:
2 to 80 psid 0.50 to 5.00 gpm, 3 to 80 psid 5.50 to 9.00 gpm
Automatic balancing valve contains a rubber diaphragm that is designed to flex into a
contoured orifice plate. This allows the valve to decrease the water flow path as pressure increases.
The pressure differential ranges of a Mesurflo automatic balancing valve cover 2 to 80 psid 2. The flexing of the rubber diaphragm against the fixed orifice plate makes the Mesurflo valve difficult to clog and resistant to cavitation damage. Outside of the pressure differential window, the controller continues to perform as high as 150 psid, but does not become a fixed orifice.
As system pressures change (through further addition of heat pumps, for example) each individual flow control valve will automatically adjust to the new system conditions.
In variable water volume applications, there can be large variations in the system water pressure. These pressure changes can adversely affect the system balance and heat pump operation. A self-balancing hose kit provides continuous balancing in this application because of its ability to automatically adjust to the varying system conditions.
Advantages:
• Flow accuracy of ±10%.
• Broader application in variable water volume pumping systems.
• Greater flow accuracy results in operation closest to design, with least tenant complaints.
• Only one pressure differential range of 2 to 80 psid 1
• Labor savings during balancing can offset increased material cost.
Automatic balancing valve hose kit example: