Name: SSC131.09U Siemens Actuator (S55155-A108)
Brand: Siemens
SKU: SSC131.09U
Availability: InStock

Siemens SSC131.09U 3-Position Floating Actuator (24 VAC, Non-Spring Return, Powermite MT Series)

Powermite MT Series actuator, 24 Vac, floating control, non-spring return. Works with MT Series valves with 7/32-inch (5.5mm) stroke. UL listed for plenum installations, manual override with LED visual position indication. Provides 65 lb. (300 N) nominal force.

The Siemens SSC131.09U is a reliable 24 VAC 3-position (floating) actuator for Powermite MT Series 2-way and 3-way valves, designed for terminal unit and VAV application environments. It is non-spring return (fail-in-place), meaning it maintains its position upon power loss. With manual override capability, LED motion and position indication, and ~67 lbf (300 N) actuation force, it delivers robust performance in fan coil units, VAV boxes, chilled ceilings, and other HVAC terminal systems.

Key Features & Benefits

24 VAC Floating Control Signal – Compatible with standard control systems using Y1/Y2 floating control.
Non-Spring Return (Fail-In-Place) – Retains last position on loss of power—ideal where fail-safe closing/opening is not required.
Strong Positioning Force – 67 lbf (≈300 N), capable of driving Powermite MT Series valves over the full stroke.
Compact Stroke Length – ~5.5 mm (≈0.22″) stroke, suited to MT Series globe valves.
LED Position & Motion Indication – Visual feedback for commissioning and troubleshooting.
Manual Override – Allows hand adjustment during setup or emergency maintenance.
Tool-Free Direct Mounting – Coupling nut makes installation with MT valves simple and secure.

Specifications

Specification	Value
Model / SKU	Siemens SSC131.09U (S55155-A108)
Control Signal	3-Position Floating (AC 24 V, Y1/Y2)
Voltage	24 VAC, 50/60 Hz
Actuation Force	~67 lbf (≈300 N)
Stroke (MT Series Valves)	~5.5 mm (≈0.22 in)
Operating Temperature	(datasheet: ambient & medium) check – compatible with typical potable / HVAC fluid temp ranges; upstream mounting type applications (specify if medium temp allowed) Amazon Web Services, Inc.+1
Mounting	Direct to Powermite MT Series valve bodies, coupling nut, tool-free
Indicators	LED motion & position feedback
Protection / Enclosure	Standard NEMA / IP rating per Siemens spec sheet (NEMA 2 / IP20 or per datasheet) Siemens Smart Delivery+1
Manual Override	Yes

Applications & Compatibility

Terminal units: VAV boxes, fan coil units, chilled ceilings etc.
Use with Powermite MT Series two-way and three-way valves.
HVAC control applications requiring floating control signals.
Where non-spring return operation is acceptable or desired (fail-in-place).

FAQs

Q: What does “fail-in-place” mean vs “fail-safe”?
A: “Fail-in-place” means the actuator remains in its last commanded position if power is lost. “Fail-safe” would move the actuator to a default position (open or closed) when power fails. SSC131.09U is non-spring return (fail-in-place).

Q: Is there a version with feedback (modulating)?
A: Yes, there are related variants (e.g. SSC131.39U, etc.) that provide feedback or modulating control (0-10 V) and/or fail-safe action.

Q: Can multiple SSC131.09U actuators be controlled in parallel?
A: Yes—per Siemens spec, multiple actuators of the same part number can be run in parallel, provided the controller output has sufficient capacity. Amazon Web Services, Inc.+1

Q: What valves are compatible?
A: Siemens Powermite MT Series valves (2-way & 3-way) are the intended application—both normally open and normally closed versions.