Siemens Powermite 599 MT Series Owner's manual

Powermite 599
Technical Instructions
Document No. 155-308P25
EA 599-14
March 17, 2015
MT Series SQS Electronic
Valve Actuator, 24 Vac,
Floating Control (3-position)
Siemens Industry, Inc.
Description The Powermite 599 MT Series SQS85.53U Electronic Valve Actuator requires a 24 Vac
supply and receives a floating control signal to provide three-position control. The
actuator controls Powermite 599 Series MT Series terminal unit valves with a 7/32-inch
(5.5 mm) stroke. With no control voltage or in the event of a power failure, a mechanical
spring allows the valve to return to its normal (fail-safe) position.
Features •Maintenance-free with reversible motor.
•UL listed for plenum installations.
•Floating control signal input.
•Mechanical spring returns the valve to its normal (fail-safe) position in power-off
condition.
Application For use in small to medium HVAC installations with Powermite 599 Series MT Series
terminal unit valves and Siemens Building Technologies standard valves with a
7/32-inch (5.5 mm) stroke requiring a minimum of 90 pounds force (400N). They can be
used in liquid and low pressure steam service applications.
Product Number SQS85.53U Actuator prefix code 266
Ordering
Information To order a complete valve plus actuator assembly from the factory, combine the
actuator prefix code with the suffix of the valve product number. See TB251, Powermite
599 Series MT Series Terminal Unit Valve and Actuator Assembly Selection
(155-306P25) for selection procedures.
To order an actuator only, use the product number.

Technical Instructions SQS Electronic Valve Actuator, 24 Vac, 3-Position (Floating) Control, Fail-Safe
Document Number 155-308P25
March 17, 2015
Page 2 Siemens Industry, Inc.
Specifications
Power Requirements Operating voltage/frequency 24 Vac, ±20%, 60 Hz
Power Supply Earth ground, isolating Class 2,
24 Vac transformer
NOTE: Do not power more than 10
actuators with one transformer.
(Use 0.5 amp fuse on secondary
per actuator.)
Power consumption 5 VA
Control Characteristics Control signal Floating (3-position)
Y1 24 Vac power extends actuator shaft (0 to 1)
Y2 24 Vac power retracts actuator shaft (1 to 0)
Functional Operation Running time
at 60 Hz 30-seconds
Spring return time ≈8-seconds
Nominal stroke 7/32-inch (5.5 mm)
Nominal force 90 lb (400 N)
Fail-safe Mechanical spring
Agency Approvals UL UL listed to UL873
cUL certified to CSA C22.2 No. 24-93
Environmental
Conditions Ambient temperature
Operation 23°F to 122°F (-5°C to 50°C)
Transport and storage -13°F to 149°F (-25°C to 65°C)
Ambient humidity 0 to 90% rh (non-condensing)
Medium temperature 41°F to 248°F (5°C to 120°C)
Physical Characteristics
Conduit opening Knockouts for standard 1/2-inch (12.7 mm)
conduit connector
Weight 1.3 lb (0.6 kg)
Dimensions See Figure 3.
Service Kit If the actuator is inoperative, replace the unit.

SQS Electronic Valve Actuator, 24 Vac, 3-Position (Floating) Control, Fail-Safe Technical Instructions
Document Number 155-308P25
March 17, 2015
Siemens Industry, Inc. Page 3
Operation A 24 Vac control signal to Y1 extends the actuator shaft proportionately to the length of
time the signal is applied.
A 24 Vac control signal to Y2 retracts the actuator shaft proportionately to the length of
time the signal is applied.
In the event of a power failure, the SQS85.53U actuator returns the valve to its normal
(spring return) position.
Mounting and
Installation Mount the actuator in any position except with the actuator lower than the valve.
Figure 1. Mounting Positions.
Wiring Use earth ground isolating, step-down Class 2 power supplies. Do not use auto
transformers.
Determine supply transformer minimum rating by summing total equipment on circuit.
The maximum rating for Class 2 step-down transformers is 100 VA.
Do not power more than 10 actuators with one transformer. (Use 0.5 amp fuse on
secondary per actuator.)
WARNING:
Housing rated for flex conduit only.

Technical Instructions SQS Electronic Valve Actuator, 24 Vac, 3-Position (Floating) Control, Fail-Safe
Document Number 155-308P25
March 17, 2015
Page 4 Siemens Industry, Inc.
Wiring Diagrams
CAUTION:
Terminals G and 21 must be properly wired for correct function and full
life of the actuator.
If the actuator makes a buzzing noise upon reaching setpoint, G and 21
are improperly wired and should be reversed.
G, 21 24 Vac operating voltage
G = System neutral
21 = System potential
Y1 Extends actuator shaft
Y2 Retracts actuator shaft
Figure 2. SQS85.53U Terminal Connections.
Start-Up The valve body assembly determines the action of the complete valve/actuator
assembly as follows:
Normally Closed Valve:
•When the actuator shaft extends, the valve opens (0 to 1).
•When the actuator shaft retracts, the valve closes (1 to 0).
Normally Open Valve:
•When the actuator shaft extends, the valve closes (0 to 1).
•When the actuator shaft retracts, the valve opens (1 to 0).
Three-Way Valve:
•When the actuator shaft extends (0 to 1), the valve opens between
port A and AB.
•When the actuator shaft retracts (1 to 0), the valve opens between
port B and BA.

SQS Electronic Valve Actuator, 24 Vac, 3-Position (Floating) Control, Fail-Safe Technical Instructions
Document Number 155-308P25
March 17, 2015
Information in this publication is based on current specifications. The company reserves the right to make changes in specifications and models as
design improvements are introduced. Product or company names mentioned herein may be the trademarks of their respective owners.
© 2015 Siemens Industry, Inc.
Siemens Industry, Inc.
Building Technologies Division
1000 Deerfield Parkway
Buffalo Grove, IL 60089
USA
+ 1 847-215-1000
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Document No. 155-308P25
Printed in the USA
Page 5
Troubleshooting Check wiring for proper connections and secure attachments.
Check for adequate power supply.
Dimensions
Figure 3. Dimensions of the SQS85.53U Actuator.
Dimensions shown in Inches (Millimeters).
Service Envelope Minimum access space recommended
4 inches (100 mm) 8 inches (200 mm)