Description
The ABB MT701.2 is a heavy-duty damper actuator from the MT Series, designed for industrial combustion and HVAC applications requiring precise modulating control. It positions air dampers, flue gas recirculation dampers, or butterfly valves based on a standard 0-10 VDC or 4-20 mA command signal from a burner management system or PLC.
This unit delivers 10 Nm of torque with a 60-second runtime, providing the mechanical advantage needed for larger dampers with tight seals. It accepts either 24 VAC or 24 VDC power and includes two adjustable auxiliary switches for end-position indication or interlock logic . The IP54 enclosure makes it suitable for installation in equipment rooms or light industrial environments where dust and water spray are present.
Frequently Asked Questions
Q: Does the MT701.2 support modulating control or just on/off?
This model is configured for modulating (proportional) control. It accepts a 0-10 VDC or 4-20 mA signal to position the damper anywhere between 0 and 90 degrees. However, the unit can also be wired for 2-position or 3-position (floating) control if needed, making it versatile for different system requirements.
Q: Can I replace an older Sachs actuator with this ABB model?
Yes. ABB acquired the Sachs burner controls line. The MT701.2 is the direct replacement for legacy Sachs models with similar specifications. Verify the mounting flange dimensions and shaft coupling type against your existing installation. The mounting pattern is standard for the MT series, but linkage adapters may be required for non-ABB applications.
Q: How do I set the auxiliary switches?
The two auxiliary switches are adjustable via independent cams located under the cover. You set them by rotating the cam to trip the microswitch at the desired angle. The most common mistake is setting them without verifying the full mechanical range of the damper. Always manually jog the actuator to the mechanical end stops first, then set the switches 5-10 degrees before the stops to prevent over-travel damage.
Q: What happens if I lose the control signal? Does the actuator fail in place?
The behavior depends on how you wire it. With no control signal, the actuator will typically remain in its last position. If you need a defined fail-safe position (open or closed), you must add an external spring-return module or specify a different actuator model. The MT701.2 does not contain an internal return spring.
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