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Honeywell - MS4120A1209 - 175in-lb 120v Two Pos Sprg Retn w/ Aux S 100-250Vac

 Two-position, SPST, spring return, 175 lb-in., 20 Nm, direct-coupled actuator 100-240 VAC


Honeywell MS4120 175lb-in. (20Nm) torque, spring return, direct-coupled, line voltage actuator accepts two-position control for use in HVAC systems. It drives quarter-turn, final control elements requiring spring return fail-safe operation.



  • Brushless DC submotor with electronic stall protection for floating/modulating models; brush DC submotor with electronic stall protection for two-position models
  • Self-centering shaft coupling for various shaft sizes
  • For use with two-position, SPST, line- (Series 40) or low- (Series 80) voltage controls
  • For use with floating or switched SPDT (Series 60) controls; use with proportional current or voltage (Series 70) controls
  • For use with proportional current or voltage (Series 70) controls; available with adjustable zero and span
  • Available with combined floating and modulating control in a single device and with line-voltage internal end switches
  • Access cover facilitates connectivity
  • Field selectable spring return direction and shaft position indicator and scale
  • UL listed (cUL), CE compliant and plenum rated per UL873


Customer Rating: Not Rated Yet
Quick Order Number: 521
Manufacturer: Honeywell
Part Number: MS4120A1209/U
Weight: 7.00 lbs
Stocked Item*: Yes
Quantity Available*: 1
Price: $437.87

* If an order is placed where the item is a "Non-Stocked Item" or the quantity ordered is more than the quantity available, all items in stock will be shipped and the remainder of the items will be shipped as soon as we get the "backordered" items in.


Product Specifications

Product Specifications

Dimensions (in.)
9.72 in high x 3.94 in wide x 2.95 in deep
Dimensions (mm)
247 mm high x 100 mm wide x 75 mm deep
Mounting bracket, self-centering shaft adapter, 3mm crank
Weight (lb)
6 lb
Weight (kg)
2.72 kg
Aluminum housing, Plenum rated plastic access cover
Integral 1/2 in. NPSM conduit connection.
Direct Coupled
50 Hz; 60 Hz
Approvals, Underwriters Laboratories Inc.
UL873, Plenum Rated
Electrical Connections
Enclosed screw terminal strip (22 to 14 AWG)
Operating Humidity Range (% RH)
5 to 95% RH, non-condensing
Supply Voltage
100 to 250 Vac
Power Consumption
Driving-- 60 VA, Holding-- 13 VA
Shipping and Storage Temperature Range (F)
-40 F to +158 F
Shipping and Storage Temperature Range (C)
-40 C to +70 C
Approvals, CE
89/336/ECC, 73/23/EEC
Approvals, Canadian Underwriters Laboratories Inc.
cUL C22.2 No. 24-93
Ambient Temperature Range (F)
-40 F to +140 F
Ambient Temperature Range (C)
-40 C to +60 C
Switch Ratings
250 Vac, 5 A res
Approvals, C-Tick
Environmental, Electrical or Ingress Protection Rating
Internal Auxiliary Switch
Maximum Noise Rating
Driving (dB(A) @ 1m)-- 40; Holding (dB(A) @ 1m)-- 20 (no audible noise)
95 ±3 degrees
Shaft Dimensions (in.)
3/8 to 1.06 in. round or 3/8 to 11/16 in. square
Actuator Type
Damper; Valve
Control Signal
Two position; SPST
Fail Safe Mode
Spring Return
Torque Rating (lb-in.)
175 lb-in.
Torque Rating (Nm)
20 Nm
Spring Return Torque/Force (lb-in., lbf)
175 lb-in.
Spring Return Torque/Force (Nm, N)
20 Nm
Additional Torque Ratings (lb-in.)
Maximum Stall-- 300 lb-in.
Additional Torque Ratings (Nm)
Maximum Stall-- 34 Nm
External Auxiliary Switches Available
Yes, SW2-US
Rotational Stroke Adjustment
Mechanically limited 5 degree increments
Timing, Nominal
Driving @ 60 Hz-- 45 sec
Spring Return Timing
Maximum-- 20 sec
Shaft Adapter Type
Self-centering clamping
Manual operation
Manual crank
Shaft Dimensions (mm)
10 to 27 mm round or 10 to 18 mm square
Spring Return Direction
By orientation



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