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SF-2 ADJUST SHURFLO PRESSURE SWITCH
The ShurFlo feed pumps are equipped with a high pressure cut out switch (part no. EL-FP-
PS). This is the small black unit on the end of the wetted end of the pump head (part no. PL-
PMP-SFPH) where the two red wires connect. If the pressure switch is not properly adjusted
the pump may cut out each time the Clark Pump cycles and the feed pressure spikes. When
this happens, the production will drop and an unusual noise will be heard when operating with
two pumps, but the system will function normally during one pump operation on either pump.
The points in the switch will fail fairly quickly if set too low because of the constant arcing
from cutting out each time the Clark pump shifts.
For all systems except the Gulfstream, the feed pump pressure switches should be set to shut
off at 125 psi (8.5 bar) as follows. On the very center of the switch is a small 5/64” allen
screw. Run the system on pump one and close the brine discharge valve (1/2 way 90 deg) to
block the flow. Watch the pressure gauge and adjust the pressure switch to shut off at 125
psi. Repeat for pump two. Turn the allen screw clockwise to increase the cut off set point.
Gulfstream models could experience seal failures in the manifold if pressurized too high. For
this reason, the pump should be removed from the system and the switch adjusted using a
separate pressure gauge. If replacing a feed pump or pump head for a Gulfstream model ar-
range to preset the switch before installation.
8/05/04