Part 2: Why Automatic Flow Control Valves should be preferred over Manual Flow Control Valves?

In Part 1 we discussed the basics of flow control valves. Selection of the two control valves will change for every application, but below are some key benefits of Automatic Control Valves (ACV’s) operation over Manual valves operation:

Pictured: Model 2519 Mesurflo

  • Better Control: Automatic Valves maintain constant flow irrespective of the system pressure variations, thereby eliminating any balancing issues. Whereas in case of Manual Valves, the flow rate varies with any change in system pressure, thereby losing balancing control capability. Hence the system will need to be monitored and re-balanced again.
  • Cost Effective: Automatic Valves are more expensive than Manual Valves, but with an automatic balancing option the valves only need to be installed at the terminals as oppose to all the distribution lines, branches and risers. Saves money for installation cost.
  • Less Maintenance: ACV’s regulate the flow at constant rates according to their pre-set values. Once they are installed in the system, they do not require any balancing labor cost or any repetitive maintenance for monitoring.
  • Easy to install/accessible: ACV’s are easy to install. Moreover, they are easy to calibrate and the flow cartridge can be easily replaced or changed in the same valve rather than replacing the whole valve body.
  • Better Stability: Poor valve sizing can cause major balancing issues throughout the system whereas Automatic Valves are typically sized by designed flow rates only.
  • Energy Efficient: ACV’s are always endorsed for saving pump energy cost with added benefits of better chiller and cooling tower performance.
  • Ease to future extension: ACV’s eliminate the need for balancing labor and allows coils to be added or removed from the existing system without needing to re-balance the entire HVAC system. In the case of manual valves, the balancing is lost even if the load demand fluctuates in any of the existing branches. Moreover, complete re-balance may be required in cases of any addition or removal of coils.Pictured:

ACV’s provide much better system balance and control. The system will run more efficiently at all the load conditions. Ultimately, this will help to save the associated pump energy cost and make the whole system perform energy efficiently while achieving proper thermal comfort.

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