F−1031, Section 2312
Page 1 of 10
Rev: 02/27/06
Principles of Operation
Before any centrifugal pump can be operated, it must be
primed. Priming is the process of replacing air in the intake
lines and portions of the pump with water. If the pump is to
be operated from draft, priming must be done by means of a
positive displacement pump, or some other device for creat-
ing a partial vacuum. Also, when pumping from a water tank,
priming will be accomplished more quickly and positively if a
priming device is used. Priming will occur naturally when
pumping from hydrants or in relay, because inlet water pres-
sure is high enough to force air out of the pump and intake
lines, providing a discharge line is opened to permit the air to
escape.
A Waterous priming system consists of a priming pump and a
priming valve. The priming pump draws air out of the centrifu-
gal pump through the priming valve. The priming valve must
be open when priming the pump and then closed when the
pump is fully primed (pumping water with all air removed).
On some models, a lubricant is needed to help seal and lubri-
cate the priming pump.
Pumping from Draft
To obtain a quick prime & maintain pump perfor-
mance:
a.) Position pump as near as possible to water supply.
b.) Avoid humps or sharp bends in intake hose. Make sure
no part of hose is higher than pump intake inlet. (Air
pockets in intake hose may cause loss of prime or erratic
pump action and may reduce pump capacity.)
c.) Make sure all intake connections are tight and discharge
valves are closed.
d.) Always use an intake strainer or screen.
e.) Immerse intake strainer at least two feet below water sur-
face to prevent pump from drawing air. (Whirlpools form-
ing above intake strainer indicate that strainer is too close
to surface of water.)
f.) Make sure intake strainer is far enough from bottom to
prevent pumping sand, gravel or other foreign matter.
Figure 1. Priming System
IL2130
Note: If pump fails to prime or loses prime,
refer to the troubleshooting guide in form
F−1031, Section 1000.
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