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Belimo Actuators Automatic Valve Control - Many processes or actions in HVAC are made more efficient by having them automatically controlled by the control system. This enhancement of efficiency is possible by using Belimo actuator valve control. The Belimo automatic HVAC valve control is made possible with DDC and modulating electric Belimo actuators.
Belimo Actuators Automatic Valve Control
This actuator can modulate the valve to regulate the flow of water through the pipe. This actuator is mounted on a valve that regulates the amount of chilled water flow that gets to the chilled water coil. If the set point of the supply air temperature is low the valve modulates open until the setpoint is reached or until the actuator modulates to 100 percent. If the supply air temperature raises then the valves close off some.
The actuator can maintain the position of the valve from 0 to 100 percent and anywhere in between based on preset variables which control the supply air temperature setpoint of the air handler. The actuator modulates based on a voltage or current signal which is received from a DDC solid-state controller. All this makes it possible for automatic HVAC valve control which enhances efficiency and saves energy dollars for the building owner and end-user.
Belimo Actuators Automatic Valve Control | Control
These actuators are typically controlled by a microcontroller for an air handler. When the programmed setpoint, which can be vary depending on the program variables, changes, the valve will open and close. The action for moving the valve opened or closed is done by a signal fed to the actuator. This will tell the actuator where the valve position should be based on the program.
If several VAV boxes are calling for cooling then the valve will actuate to a more open position increasing chilled water flow through the coil inside the VAV air handler. If fewer VAV boxes need cooling then the valve will close off some to reduce the amount of chilled water needed to satisfy the demand. This action has an effect on the chilled water pumps that are usually controlled by Variable Frequency Drives (VFDs) to modulate the flow of water. They work off of another microcontroller that will modulate the flow based on a pressure set point in the chilled water piping.
Control Considerations | Belimo Actuators Automatic Valve Control
When determining the type of actuator you need for control you should consider these technical considerations to select the proper actuator:
- Is the valve modulating or two positions? Two-position valves will require an actuator that will open or close the valve depending on NO or NC (Normally Open or Normally Closed). This depends entirely on the control sequence. The actuators for these valves are typically energized on 24-volts or 120-volts. When power is off for the actuator it typically is spring return to the opposite position. A modulating actuator will require an analog signal typically 4-20 MilliAmps or 2 to 12 or 0 to 10 volts DC. The modulating range is set up in the control parameters of the DDC controller.
- The torque is necessary to control the valve effectively.
These things are typically set up correctly by the control engineer in the design phase. However, I’ve seen maintenance people make replacements with incorrect actuators when they think an actuator is bad. If an actuator is bad, the best option is an exact replacement. For whatever reason, this advice is not always followed.
Belimo Actuators HVAC Automatic Valve Control | Conclusion
This all sounds complicated to a layman but is actually very simple and efficient in providing cooling for a large building with lots of zones. To learn more see our Building Automation/DDC pages.
Belimo Actuators HVAC Automatic Valve Control
