The Siemens GBB166.1U is a non-spring-return rotary damper actuator from the OpenAir line, delivering 221 in-lb [25 Nm] of torque for air dampers up to roughly 44 sq ft. It runs on 24 VAC/DC, uses a brushless DC motor with a self-centering shaft coupling, and holds its last position on power loss (non-spring-return). It accepts a modulating 0/2-10 VDC signal with self-adapting rotation range and a 0-10 VDC position-feedback output. Two independently adjustable SPDT auxiliary switches signal damper position or interlock equipment. Wiring is pre-cabled with standard cable.
Specifications sourced from the official Siemens datasheet A6V14252663 + NA technical instructions.
Overview
Siemens OpenAir GBB-Series actuators are direct-coupled, non-spring-return rotary damper actuators for ventilation and air-conditioning systems — regulating and shutting off air dampers in return-air, mixed-air, exhaust, and face-and-bypass applications. The GBB166.1U produces 221 in-lb [25 Nm] (up to 336 in-lb [38 Nm] blocked) and drives a 90° stroke in about 150 seconds. Its brushless DC motor is overload-protected and holds position at the end stop and on power loss. This is the standard-cable version. UL and cUL listed.
Best for
- Return-air, mixed-air, and exhaust damper control
- Face-and-bypass and general HVAC damper applications
- Constant- and variable-air-volume systems needing 221 in-lb torque
- Applications that should hold position on power loss
- Damper end-position signaling or equipment interlock (2x SPDT)
Key Features
221 in-lb Non-Spring-Return
Drives air dampers up to ~44 sq ft and holds the last position on power loss — no spring return.
Modulating + Feedback
Accepts a 0/2-10 VDC modulating signal with self-adapting rotation range and a 0-10 VDC feedback output.
Brushless DC Motor
Maintenance-free brushless DC motor with silicone-free gears; overload-protected across the full range.
Self-Centering Coupling
A self-centering shaft coupling fits round shafts 3/8-1 in. and square shafts 1/4-5/8 in. for fast mounting.
Dual Adjustable Aux Switches
Two independent SPDT switches (A & B), each set 0-90° in 5° steps; rated 6 A resistive at 24-250 VAC (standard cable).
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Siemens (OpenAir) |
| Part Number | GBB166.1U |
| Actuator Type | Non-Spring-Return (Fail-in-Place) Rotary Damper Actuator |
| Nominal Voltage | 24 VAC / 24 VDC (±20%) |
| Nominal Frequency | 50/60 Hz |
| Power Consumption | Running 2.2 VA / 1.5 W; Holding 0.9 VA / 0.5 W |
| Torque (Running) | 221 in-lb [25 Nm] |
| Torque (Maximum, Blocked) | 336 in-lb [38 Nm] |
| Control Signal | Modulating 0/2-10 VDC (or 0/4-20 mA); self-adapting rotation range |
| Position Feedback | 0-10 VDC output (max. ±1 mA) |
| Angle of Rotation | 90° nominal (95° maximum) |
| Running Time | 150 seconds for 90° (50/60 Hz) |
| Behavior on Power Loss | Holds last position (non-spring-return; overload protected) |
| Manual Override | Yes — push-button gear-train disengagement |
| Motor | Brushless DC; maintenance-free, silicone-free gear lubrication |
| Shaft Coupling | Self-centering; round 3/8-1 in. [8-25.6 mm], square 1/4-5/8 in. [6-18 mm] |
| Minimum Shaft Length | 3/4 in. [20 mm] |
| Auxiliary Switches | 2x adjustable SPDT (A & B), set 0-90° in 5° steps (factory A=5°, B=85°) |
| Aux Switch Rating | 6 A resistive / 2 A general purpose at 24-250 VAC; 12-30 VDC / 2 A |
| Electrical Connection | 3 ft [0.9 m] pre-cabled, 18 AWG (standard cable) |
| Equipment Rating | Class 2 (UL/CSA) |
| Enclosure | NEMA 1 (NEMA 3R with ASK75.1U shield); IP54 per EN 60529 |
| Housing Material | Die-cast aluminum alloy |
| Ambient Temperature | -25°F to 130°F [-32°C to 55°C] |
| Agency Listing | UL listed (UL 60730); cUL (CSA E60730); CE |
| Service Life | 60,000 full-stroke cycles; 5,000,000 repositions |
| Sound Power Level | < 45 dB(A) running |
| Weight | 5 lb 2 oz [2.35 kg] |
| Warranty | 5 Years (60 months) |
Documentation
Related Products
Accessories & Mounting
Common Siemens OpenAir mounting and service accessories for the GBB166.1U.
Frequently Asked Questions
What is the Siemens GBB166.1U?
The Siemens GBB166.1U is an OpenAir non-spring-return rotary damper actuator producing 221 in-lb [25 Nm] of torque. It runs on 24 VAC/DC, provides modulating 0/2-10 VDC control, and holds its last position on power loss.
Is the GBB166.1U spring-return?
No. The GBB166.1U is non-spring-return (fail-in-place): on power loss it holds its last position. For spring-return fail-safe operation, Siemens offers separate GCA/GIB spring-return families.
What control signal does the GBB166.1U accept?
A modulating 0/2-10 VDC signal (also 0/4-20 mA). It self-adapts to the mechanical rotation range and provides a 0-10 VDC position-feedback output.
What auxiliary switches does the GBB166.1U have?
Two independently adjustable SPDT auxiliary switches (A and B), each set 0-90° in 5° increments. With standard cable they are rated 6 A resistive at 24-250 VAC; with plenum cable, 4 A resistive at 24 VAC.
What is the difference between the .1U and .1P versions?
The suffix indicates the cable: .1U is standard cable and .1P is plenum-rated cable for air-handling plenums. The GBB166.1U ships with standard cable.
What shaft sizes does the GBB166.1U fit?
Its self-centering coupling fits round shafts from 3/8 to 1 in. (8-25.6 mm) and square shafts from 1/4 to 5/8 in. (6-18 mm); minimum shaft length is 3/4 in. (20 mm).
Does the GBB166.1U have a manual override?
Yes. A push-button gear-train disengagement lets you position the damper by hand; the actuator returns to automatic control once power is restored.
Is the Siemens GBB166.1U available from an authorized distributor?
Yes. ZOT Supply stocks the Siemens GBB166.1U. Units ship factory new with the Siemens 5-year (60-month) limited warranty.
- Actuator Type:
- Non-Fail-Safe
- Torque:
- 221 in-lb
- Control Signal:
- Modulating
- Voltage:
- 24 VAC/DC
- Auxiliary Switch:
- 2x SPDT
- Enclosure:
- NEMA 1
- Feedback Signal:
- 0-10 VDC
- Cable:
- Standard
- Series:
- GBB
