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.



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