Sterling SGM-250A User Manual

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                        Water Management Systems and Products 
Page 15 
The Model SGM-250P backwashes based upon pressure 
differential across the filter media. Additionally, an adjustable 
timer allows back washing for up to five minutes. The factory 
setting is four minutes. 
 
The pressure differential switch is adjustable for pressure drop and 
dead band. Backwash will start when the pressure differential 
reaches set point plus the dead band. For example, if the pressure 
differential is set for 6 psi, the dead band for 4 psi, and the 
backwash timer for 4 minutes, then the backwash cycle will start at 
10 psi for a duration of four minutes. 
 
 
Replacing Sand and Gravel 
Replace the sand and gravel every two years, when contaminated, 
or when sand has carried over from excessive water flow.  
 
There are three layers of filter media. First, starting from the 
bottom, place 200 lbs. of ½” x ¼” round gravel.  Second, place 300 
lbs. of ¼” x 1/8” round gravel and third, the top final layer, place 
700 pounds of #20 filter sand.  
 
Anode Replacement 
On top of the filter housing is a sacrificial anode made of 
magnesium. Inspect and replace when it has depleted. 
 
 
 
5-2 Centri-Separator 
System 
The CSM-150 and CSM-400 require a 120/1/60-power source and 
are provided with a standard plug. The separators are designed to 
operate to a prescribed flow range for maximum solid removal. 
The CSM-150 operates at a flow rate of 10 to 20 gpm and the 
CSM-400 operates at 45 to 70 gpm. Liquid enters the upper portion 
of the separator housing tangentially and the solids are drawn 
through internal slots to the bottom chamber. An electrically 
operated ball valve automatically back flushes the solids from the 
separator. Periodically inspect and ensure that the purge line is 
clear to flow freely.