Belimo LF24-SR US Damper Control Actuator Instruction Manual

1. Introduction

The Belimo LF Series Actuators are designed to provide reliable spring return operation for fail-safe applications and positive close-off on air-tight dampers. The spring return system ensures consistent torque to the damper, both with and without power applied to the actuator.

The LF Series offers 95° of rotation and includes a graduated position indicator, displaying positions from 0° to 95°. The LF24-SR US model utilizes a brushless DC motor, controlled by an Application Specific Integrated Circuit (ASIC) and a microprocessor. This advanced control system provides a constant rotation rate and accurately determines the actuator's exact fail-safe position.

The ASIC monitors and controls the brushless DC motor's rotation, incorporating a digital rotation sensing function to prevent damage if the actuator stalls. The actuator can be stalled at any point in its normal rotation without requiring mechanical end switches. Additionally, power consumption is reduced when the actuator is in holding mode.

This product is manufactured in the United States by Belimo Air Controls.

Figure 1: Belimo LF24-SR US Damper Control Actuator, showing its main body and wiring.

2. Setup and Installation

2.1 Mounting

The LF24-SR US actuator is designed for screw mount installation. Ensure the mounting surface is stable and capable of supporting the actuator's weight and operational forces. Refer to the product's technical data sheet for specific mounting hole dimensions and torque requirements.

2.2 Wiring

This actuator operates on 24 Volts DC. Connect the power supply to the screw-type terminals as indicated on the actuator's label. Ensure all wiring complies with local electrical codes and standards. Incorrect wiring can lead to malfunction or damage.

• Power Supply: 24V DC
• Connector Type: Screw

Figure 2: Belimo LF24-SR US Damper Control Actuator shown with an included mounting bracket for installation.

3. Operating Principles

3.1 Proportional Control

The LF24-SR US actuator provides proportional control, allowing for precise positioning of the damper based on an input signal. This enables fine-tuned airflow regulation within HVAC systems.

3.2 Spring Return Fail-Safe Function

In the event of a power failure, the integrated spring mechanism automatically drives the damper to a pre-defined fail-safe position (e.g., fully open or fully closed). This ensures critical system responses are maintained even without electrical power.

3.3 Position Indication

A graduated position indicator on the actuator provides a visual reference of the damper's current angle, ranging from 0° to 95°.

4. Maintenance

The Belimo LF24-SR US Damper Control Actuator is designed for long-term, maintenance-free operation under normal conditions. No routine lubrication or adjustment is typically required.

Periodically inspect the actuator and its connections for any signs of wear, damage, or loose wiring. Ensure the mounting remains secure. Keep the actuator free from excessive dust or debris.

5. Troubleshooting

If the actuator is not functioning as expected, consider the following basic troubleshooting steps:

• No Movement: Verify that the 24V DC power supply is connected correctly and is providing the specified voltage. Check all wiring connections for security.
• Incorrect Positioning: Ensure the control signal is within the expected range for proportional operation. Check for any mechanical obstructions preventing full damper travel.
• Unusual Noise: Inspect for any foreign objects or damage to the damper linkage or actuator mechanism.

For persistent issues, contact Belimo technical support or a qualified service technician.

6. Specifications

7. Warranty and Support

For information regarding product warranty, technical support, or service, please contact Belimo Air Controls directly through their official website or customer service channels. Ensure you have your product model number (LF24-SR US) and purchase details available when seeking support.