Honeywell MS8120 Series Actuators: MS8120A1205 S2024-2POS-SW2

Technical Dossier

Product Details And Specifications

Honeywell MS8120 Series: Comprehensive Module Range and Technical Overview

The Honeywell MS8120 series comprises direct coupled actuators engineered for HVAC damper and valve control in heavy industrial and commercial building automation environments. These units are deployed globally across chemical processing plants, oil refineries, pharmaceutical manufacturing facilities, and large-scale HVAC infrastructure where precise, reliable damper positioning is a non-negotiable operational requirement. The MS8120 platform operates on 24 VAC/VDC power and delivers spring-return or non-spring-return torque outputs suited for zone dampers, VAV boxes, and air handling units. Its compact direct-couple design eliminates the need for external linkage, reducing mechanical failure points in high-cycle applications. The series has established a significant installed base in North American and European industrial facilities, making long-term parts availability a critical supply chain concern for facility engineers and maintenance contractors.

The Evolution of MS8120 Architecture

The MS8120 series represents Honeywell's second-generation direct coupled actuator platform, succeeding earlier M7284 and M6284 linkage-based actuator families. The architectural shift to direct coupling was driven by field data indicating that mechanical linkage assemblies accounted for a disproportionate share of actuator-related service calls in high-cycle HVAC systems.

Early MS8120 variants (circa late 1990s–early 2000s) used analog 2-10 VDC or 4-20 mA control signals with basic end-switch feedback. Mid-generation revisions introduced the S2024 suffix designation, indicating compatibility with 24 VAC/VDC floating or proportional control schemes and the integration of auxiliary switch packages (SW2 = 2 auxiliary switches). The MS8120A1205 S2024-2POS-SW2 represents a mature configuration within this lineage: a 2-position (on/off) control mode actuator with dual auxiliary switches, designed for integration into DDC (Direct Digital Control) building automation systems.

As BACnet and LonWorks protocols became standard in building automation, the MS8120 series maintained relevance through its analog and floating control compatibility, which interfaces cleanly with most DDC controllers via standard AO/DO outputs. The series is now considered mature/end-of-production for several configurations, making aftermarket sourcing and lifecycle extension support the primary procurement pathway for maintenance operations.

MS8120 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified models within the Honeywell MS8120 direct coupled actuator series, organized by control type and output configuration:

2-Position (On/Off) Control Models

• MS8120A1205: 24 VAC/VDC, 2-position, spring return, 35 in-lb torque, standard damper actuator
• MS8120A1205 S2024-2POS-SW2: 24 VAC/VDC, 2-position, spring return, 35 in-lb, dual auxiliary switch package
• MS8120A1213: 24 VAC/VDC, 2-position, spring return, 35 in-lb, with 2-10 VDC feedback signal
• MS8120F1002: 24 VAC/VDC, 2-position, non-spring return, 35 in-lb, floating control
• MS8120F1010: 24 VAC/VDC, 2-position, non-spring return, 35 in-lb, with auxiliary switch

Floating (Tri-State) Control Models

• MS8120H1004: 24 VAC, floating control, spring return, 35 in-lb, standard configuration
• MS8120H1012: 24 VAC, floating control, spring return, 35 in-lb, with 2-10 VDC position feedback
• MS8120H1020: 24 VAC, floating control, spring return, 35 in-lb, dual auxiliary switch
• MS8120H2004: 24 VAC, floating control, non-spring return, 35 in-lb
• MS8120H2012: 24 VAC, floating control, non-spring return, 35 in-lb, position feedback output

Proportional (Modulating) Control Models

• MS8120B1006: 24 VAC/VDC, 2-10 VDC proportional input, spring return, 35 in-lb
• MS8120B1014: 24 VAC/VDC, 2-10 VDC proportional input, spring return, with position feedback
• MS8120B1022: 24 VAC/VDC, 2-10 VDC proportional input, spring return, dual auxiliary switch
• MS8120B2006: 24 VAC/VDC, 2-10 VDC proportional input, non-spring return, 35 in-lb
• MS8120B2014: 24 VAC/VDC, 2-10 VDC proportional input, non-spring return, position feedback
• MS8120B2022: 24 VAC/VDC, 2-10 VDC proportional input, non-spring return, dual auxiliary switch

High-Torque Extended Models

• MS8120A1007: 24 VAC/VDC, 2-position, spring return, 70 in-lb high-torque variant
• MS8120H1007: 24 VAC, floating control, spring return, 70 in-lb high-torque variant
• MS8120B1007: 24 VAC/VDC, proportional, spring return, 70 in-lb high-torque variant

Sourcing Hard-to-Find & Obsolete MS8120 Parts

Multiple configurations within the MS8120 series have been discontinued by Honeywell as the manufacturer transitions its actuator portfolio toward the ML series (ML6420, ML7420) and the newer ML6161/ML7161 platform. For facilities operating legacy HVAC systems with MS8120 actuators installed, direct OEM replacement is no longer a viable procurement path for many part numbers.

DriveKNMS maintains a dedicated inventory of MS8120 series actuators sourced through authorized surplus channels, decommissioned facility buybacks, and verified distributor overstock. All units are inspected prior to listing. For end-of-life models including the MS8120A1205 S2024-2POS-SW2, DriveKNMS provides:

• Cross-reference matching to identify functional equivalents within the ML series where direct substitution is feasible
• Batch procurement support for facilities requiring multiple units for scheduled maintenance shutdowns
• Documentation packages including original Honeywell installation sheets and wiring diagrams where available
• Lead time commitments for hard-to-find configurations with typical fulfillment within 5–15 business days

Quality Control for the MS8120 Range

Direct coupled actuators present specific inspection challenges due to their integrated gear train, spring-return mechanism, and embedded auxiliary switch assemblies. DriveKNMS applies the following test protocol to all MS8120 units prior to shipment:

• Torque output verification: Each unit is bench-tested under rated load (35 in-lb or 70 in-lb per model specification) to confirm full torque delivery at both 24 VAC and 24 VDC supply voltages.
• Spring return function test: Spring-return models are cycled through a minimum of 10 full-stroke open/close sequences with power interruption at mid-stroke to verify spring return speed and full closure.
• Auxiliary switch calibration: SW2-equipped models (including the MS8120A1205 S2024-2POS-SW2) have both auxiliary switches tested for actuation point accuracy at the factory-set positions (typically 10° and 60° of rotation).
• Control signal response: Proportional and floating control models are tested with a calibrated signal generator to verify linearity of response across the full 2-10 VDC or tri-state input range.
• Enclosure and connector inspection: All units are inspected for housing integrity, terminal block condition, and cable jacket status. Units with damaged connectors or cracked housings are rejected.

For procurement inquiries, cross-reference requests, or bulk order quotations on Honeywell MS8120 series actuators:

• Email: [email protected]
• WhatsApp: +86 18359293191
• Web: driveknms.com