4 Starting Pump
4.1 Checking for free turning
Rotate shaft by hand to be sure rotating element is free. If element rubs or binds:
1.
Check alignment.
2. Pipe loads should be removed.
3. Check impeller clearance (if external adjustment is possible) as outlined in Sect 6.2 Impeller
clearance adjustment on page 35.
4. If unit is equipped with leveling bolts on frame or casing foot, check to be sure that bolts are not
overtightened.
4.2 Regulation of cooling and flushing liquids
The supplu of liquid to any cooling jackets, quench glands, or mechanical seals should be regulated by
valves in the supply line. Approximate flow rates are as follows:
Quench glands ½ to 1 GPM
Cooling jackets 1 to 3 GPM
Mecnanical Seals ½ to 2 GPM
The cooling lines should be checked periodically to see that they have not become clogged.
4.3 Priming
The pump must always be fully primed and the suction pipe full of liquid before pump is started.
If pump is run dry
, the rotating parts within the pump may seize to the stationary parts since they depend
upon the liquid being pumped for lubrication.
Several different methods of priming can be used, depending upon the type of installation and service
involved.
Vertical sump pumps, when submerged, need not be primed since the pump is filled with liquid.
NOTICE:
On glass-lined pumps, the thermal shock limit of the glass varies with the conditions of opera-
tion. Do not introduce liquid to pump if temperature dif
ference between liquid and pump is over
100ºF. Gradually heat pump before introducing hot liquids.
Suction supply above pump
Figure 22: Suction supply above pump
4 Starting Pump
Model 3415 Installation, Operation, and Maintenance Manual 27
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