suction pipe and pump casing. When all air is evacuated, start pump, close valve "S' and valve "E". and
open discharge gate valve.
Figure 26:
Priming by automatic primer pump
Where there is a fluctuating suction lift that occasionally might drop below the normal limits of the pump,
or for installations where there is any quantity of air entrained in the pumpage, the system shown in Fig-
ure 27: on page 30 is very well adapted.
A vacuum tank and a vacuum gauge can be installed near the primer pump and the vacuum switch set
to automatically start or stop the primer pump according to the vacuum required to keep the system
primed.
Figure 27:
4.4 Initial inspection after starting
Packed box
With pump running at rated speed, the stuf
fing box gland can be adjusted. Draw gland nuts up evenly
and only 1/6 of a turn at a time, allowing sufficient time between adjustments for the packing to adjust
itself and the effect on the leakage to be observed. If any sign of heating is evident, shut down the pump
and allow the box to cool. Several starts may be necessary before the box runs coo. Do not back off the
gland nuts on a hot box as this will usually result in liquid leaking between the outer edge of the packing
and the stuffing box bore. Remember that it takes newly installed packing some time to run in and that
4.4 Initial inspection after starting
30 Model 3415 Installation, Operation, and Maintenance Manual
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