The Belimo AFBUP-S is a spring-return (fail-safe) damper actuator designed for HVAC systems, offering reliable performance in a wide range of environmental conditions. With a torque rating of 180 in-lb and compatibility with both AC and DC power sources, the AFBUP-S is a versatile solution for applications requiring on/off control signals. This article provides a detailed overview of the technical specifications, environmental tolerances, and installation considerations for the AFBUP-S actuator, based exclusively on the provided source data.
Technical Specifications and Operational Features
The AFBUP-S actuator is engineered to deliver consistent performance under varying electrical inputs and ambient conditions. Its specifications reflect a balance between efficiency, durability, and adaptability to different installation environments.
Power and Electrical Compatibility
The AFBUP-S supports a wide range of input voltages, making it suitable for use in systems with diverse power configurations. It is compatible with:
- AC Voltage: 24 to 240 VAC
- DC Voltage: 24 to 125 VDC
This broad voltage range ensures flexibility for users integrating the actuator into existing HVAC systems without requiring significant modifications to the electrical infrastructure.
The actuator consumes 7 watts of power during operation and 3.5 watts during the holding phase. For wire sizing purposes, the power consumption is specified as 18 VA, which is an important factor for determining the appropriate gauge and type of wiring to use.
Mechanical and Functional Attributes
The AFBUP-S is designed to provide a 180 in-lb torque output, which is sufficient for actuating a wide variety of damper sizes and types. The actuator operates through an on/off control signal, meaning it functions in a binary manner—either open or closed—without intermediate positions.
The angle of rotation is specified at 95 degrees, and the actuator requires 75 seconds to complete a 90-degree rotation when powered. In the event of a power failure, the fail-safe mechanism engages, returning the damper to a predefined position. This fail-safe operation is executed in less than 20 seconds, ensuring rapid response during outages or system malfunctions.
The direction of motion and rotation can be adjusted based on the mounting orientation. Specifically, the direction of motion of the motor is selectable by ccw/cw mounting, while the direction of rotation in fail-safe mode is reversible with cw/ccw mounting. This adaptability allows the actuator to be integrated into different system layouts without requiring additional mechanical modifications.
A manual override feature is also included, which allows for manual adjustment of the damper position when necessary. The override is performed using a 5 mm hex crank (3/16" Allen key), which is supplied with the actuator. This feature is particularly useful for maintenance, commissioning, or emergency overrides when electrical power is unavailable.
Environmental and Protection Ratings
The AFBUP-S is designed to operate in environments with a wide range of ambient temperatures. It can function reliably in temperatures ranging from -22°F to 122°F (or -30°C to 50°C), making it suitable for both indoor and outdoor HVAC applications. The actuator is rated with an IP42 protection class, which means it is protected against solid objects larger than 1 mm in size and splashing water from any direction. This level of protection ensures that the actuator can withstand typical environmental exposure without internal damage.
In terms of NEMA (National Electrical Manufacturers Association) ratings, the AFBUP-S is classified under NEMA 2, which corresponds to a general-purpose enclosure that is suitable for indoor use and provides protection against dust, light spraying of water, and accidental contact. The enclosure type also aligns with UL Enclosure Type 2, reinforcing its compliance with U.S. electrical safety standards.
It is important to note that the AFBUP-S does not feature a NEMA 4X enclosure, which would offer additional protection against corrosion and more severe weather conditions. Therefore, it is not recommended for use in environments where exposure to saltwater, heavy rain, or extreme weather is expected.
Installation and Mounting Considerations
The installation of the AFBUP-S requires careful planning and adherence to the manufacturer’s guidelines to ensure proper functionality and longevity. While specific installation instructions are not included in the provided source data, several key factors can be inferred based on the technical specifications and general best practices for damper actuators.
Mounting Orientation and Directional Adjustments
One of the critical aspects of installation is determining the mounting orientation of the actuator. The AFBUP-S allows for directional adjustments based on how it is mounted—specifically, the motor's direction of motion can be set to either clockwise (cw) or counterclockwise (ccw). This flexibility is essential for aligning the actuator with the damper’s mechanical linkage and ensuring that the open and close positions correspond to the intended control signal.
Users must ensure that the actuator is mounted in a way that allows the damper to reach its full range of motion without binding or misalignment. This may require adjusting the mounting bracket or using additional mechanical linkages to accommodate the damper’s stroke length.
Electrical Connections and Wire Sizing
The actuator requires a reliable electrical connection to function correctly. The 18 VA power consumption rating is a key consideration when determining the appropriate wiring. Users must ensure that the electrical conduit and wiring used are capable of handling the actuator’s power demands without causing voltage drops or overheating.
The AFBUP-S can be powered by either AC or DC sources, but the wiring and terminal connections must be configured accordingly. It is important to follow the manufacturer’s wiring diagrams (if available) to ensure that the connections are made correctly and that the actuator is grounded and protected against electrical faults.
Fail-Safe Mechanism and Testing
As a fail-safe actuator, the AFBUP-S is designed to return the damper to a safe position in the event of a power failure. During installation, it is essential to verify that the fail-safe mechanism operates correctly and that the damper reaches the intended position when the power is removed.
Testing the fail-safe function should be part of the commissioning process. This can be done by simulating a power outage and observing the damper’s response. If the damper does not move to the correct position, adjustments to the mounting or mechanical linkage may be necessary.
Environmental and Location Considerations
Given the IP42 and NEMA 2 ratings, the AFBUP-S is suitable for installation in indoor environments where it is protected from direct exposure to water, dust, and physical contact. Users should ensure that the actuator is installed in a location that allows for proper ventilation and access for maintenance and inspection.
If the actuator is to be installed in a location with potential exposure to moisture or dust, additional protective measures—such as installing a cover or using a higher-rated enclosure—may be necessary to ensure long-term reliability.
Conclusion
The Belimo AFBUP-S is a robust and adaptable spring-return damper actuator designed for use in HVAC systems. Its compatibility with a wide range of voltages, on/off control signals, and fail-safe functionality makes it a reliable choice for applications requiring consistent and secure damper control. With a torque rating of 180 in-lb and a rapid fail-safe response time of less than 20 seconds, the AFBUP-S ensures efficient and dependable performance in a variety of environments.
Installation requires careful attention to mounting orientation, electrical connections, and environmental conditions to ensure optimal operation. While the provided source data does not include detailed installation instructions, the specifications and operational features outlined in the documentation provide a solid foundation for planning and executing the installation process.
For users seeking more detailed guidance, it is recommended to consult the Belimo AFB Series Installation Instructions and Mounting Methods Guide, both of which are referenced in the source data. These documents will likely provide step-by-step procedures, diagrams, and additional technical considerations for integrating the AFBUP-S into a larger HVAC system.