Siemens S55180-A151 Powermite MZ Series Non-Spring Return Actuator 24VAC 0-10VDC

The Siemens S55180-A151 (also known as SSB161.05U or SSB61U) is a Powermite MZ Series electromotoric valve actuator designed for precise control of HVAC zone valves and dampers in commercial and residential building automation systems.

Key Features:

• 24 VAC/DC operating voltage with 0-10 VDC proportional control signal
• Non-spring return (fail-in-place) operation maintains last position during power loss
• Compatible with Powermite 599 MZ Series two-way and three-way globe valves
• 7/32-inch (5.5mm) stroke for precise valve modulation
• Provides 45 lbf (200 N) nominal actuating force
• UL listed for plenum installations ensuring safety compliance
• Manual override with LED visual position indication for easy troubleshooting
• Operating temperature range: 34°F to 122°F (1°C to 50°C)
• Low power consumption: 2.5 VA for proportional control

This actuator is ideal for applications including air handling units, terminal units, mixing boxes, zone control, fan coil units, and radiant heating/cooling systems. The compact design allows installation in tight spaces, while the threaded valve bonnet connection ensures secure mounting. The non-spring return design provides reliable system stability and energy efficiency by maintaining valve position during power interruptions.