Product Overview

Technical Bulletin MT Series Terminal Unit Valve and Actuator Assembly Selection
Document Number 155-306P25
October 27, 2015
Page 2 Siemens Industry, Inc.
Selection Example
Specifications
In an ANSI 250 piping system, a two-way, normally closed (NC), female-by-female
(F×F) NPT threaded valve is to deliver 20 gpm (4.5 m
3
/h) chilled water with no more
than 5 psi (35 kPa) pressure drop across the fully open valve.
The actuator is to receive 24 Vac power, supply a floating control signal, and provide
spring return (SR) operation. The actuator is to close off tightly against a pump head
pressure of 15 psi (103 kPa, 1 bar).
Valve Sizing
Use Figure 1, the water capacity graph, to select the valve size as follows:
1. Locate the required flow rate by finding 20 gpm (4.5 m3/h) on the vertical axis.
2. Follow across the horizontal axis to find the 5 psi (35 kPa) maximum allowable
pressure drop across the open valve.
3. Since the point of intersection is near a 1-inch (25-mm), 10 Cv (8.5 Kvs) valve size,
select that valve size to ensure proper flow.
Actuator Selection
Use Figure 2, the maximum close-off pressure graph for actuators on two-way valves,
to select an actuator as follows:
1. For NC valves with electronic actuators, choose the upper left graph.
2. Locate the 3/4-inch to 1-inch bar to correspond to the 1-inch (25-mm) valve size.
Note that the top of the bar or the maximum close-off pressure is 40 psi (276 kPa).
3. The 40 psi (276 kPa) close-off rating of the SAS Series actuator will close-off tightly
against a pump head pressure of 15 psi (103 kPa, 1 bar).
Assembly (Product
Number) Selection
Use Table 3, two-way normally-closed valve assemblies, to select a valve and actuator
assembly as follows:
1. Read the table from left to right and select bronze trim for the low pressure, chilled
water application; and F×F for NPT valve threads. Select a 10 Cv (8.5 Kvs), 1-inch
(25-mm) valve size, determined from the preceding valve sizing example. The valve
body part number is 599-02014.
2. Read across the top of the table and select a 24 Vac actuator with floating control
signal and spring return (SR) operation. The actuator part number is SAS81.33U.
The actuator prefix code number is 366.
3. Read down the SAS81.33U actuator column and across the 599-02014 valve body
row. The column/row intersection determines the appropriate valve and actuator
assembly, which is 366-02014.
The valve and actuator can be ordered separately by using the part numbers from steps
2 and 3.