Xylem GSSERVICE R2 Service Manual Submersible Pumps & Jet Pumps - Manual (Page 7)

5
TYPIC
AL
S
YS
TEM
Motor Cooling, Temperature
and Time Ratings
All 4 inch CentriPro motors may be
operated continuously in water up to 86º
F. Optimum service life will be attained
by maintaining a minimum flow rate past
the motor of .25 feet per second. Use a
Flow Sleeve if velocity is below the .25'/
sec, if the well is top feeding or when the
pump is used in a large body of water or
large tank.
Six (6) inch canned design motors from
5 – 40 HP will operate in water up to
95º F (35º C), without any de-rating of
horsepower, with a minimum flow rate of
.5 ft./sec. past the motor. 6" – 50 HP and
all 8" – 10" motors can operate in 77º F
(25º C) water with .5'/sec velocity past
the motor.
One way to make a flow sleeve is to install a well seal
above the pump discharge and slip a piece of casing
over the pump and affix it to the well seal. Drill three
holes at 120º intervals on the lower section of the casing
and insert (3) screws and nuts through the casing, just
touching the motor. Tighten the nuts out against the
casing. Insure that the screws do not protrude out too
far as you don’t want them catching on well joints.
Pump Cooling and Lubrication
In addition to motor cooling, another reason to
maintain minimum flow rates is pump lubrication. All
manufacturers’, either on curves or in selection charts,
show minimum flows. This insures that rotating pump
parts are properly lubricated to prolong service life and
reduce friction. A dead headed pump will super heat
water very quickly, and hot water has no lubricity.
FLOW SLEEVE