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Valve Selection
The recommended valve for a feedwater application is a Siemens Flowrite VF 599 series, two-way, normally closed, high-
temperature, with an ANSI class pressure rating of 250 lbs. This is a Class IV valve, which means it has an allowable
leakage rate of .01% of rated flow at installed dP. A Valve is typically sized for two requirements; flow rate in GPM (usually
1.1 to 1.5 times the maximum flow rate to the boiler) and the available differential pressure in PSI.
Example:
A 40 GPM flow rate with a differential pressure of 6 PSI, suggests a 1-1/4" bronze valve with a CV of 16, and 3 / 4" stroke.
The system must be designed so that the maximum pump pressure on start up, (no pressure in boiler) when the valve is
closed does not exceed the maximum rated close off differential pressure rating of the valve body.
Please see Technical Instructions for maximum pressure rating vs. temperature, and capacity graph.
Electric Actuators Selection
The valve selected above can then be combined with a Siemens Flowrite EA 599 series, 24VAC, Electronic Proportional
Control actuator. The actuator housings are all rated NEMA 1, all accept 4-20 mA inputs, and can be configured for normal
or reverse acting. Refer to the chart below for actuator, order number, stroke, force, and run time.
Order Number
SKD 62UA
SKC 62UA
SKB 62UA
CCxx-Feedwater
Preliminary
- Pg 3 of 6
Stroke
Force
3/4"
20mm
225 lbs.
1-1/2"
40mm
640 lbs.
3/4"
20mm
3/4"
20mm
640 lbs.
05.12.2003
Technical
Run time
Instructions
30 sec
120 sec
155-717
60 sec
120 sec
Siemens Building Technologies
Installation
Instructions
129-369
129-368
HVAC Products
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