Figure 18:
Suction Lift Conditions
1.
Suction pipe must be free from air pockets.
2.
Suction piping must slope upwards to pump.
3.
All joints must be air tight.
4.
A means of priming the pump must be provided, such as a foot valve, except for the 3796 self
priming pump.
Suction Head / Flooded Suction Conditions
1.
An isolation valve should be installed in the suction line at least two pipe diameters from the suc-
tion to permit closing of the line for pump inspection and maintenance.
2.
Keep suction pipe free from air pockets.
3.
Piping should be level or slope gradually downward from the source of supply.
4.
No portion of the piping should extend below pump suction flange.
5.
The size of entrance from supply should be one or two sizes larger than the suction pipe.
6.
The suction pipe must be adequately submerged below the liquid surface to prevent vortices and
air entrainment at the supply.
3.6.3 Discharge piping
1.
Isolation and check valves should be installed in discharge line. Locate the check valve between
isolation valve and pump. This will permit inspection of the check valve. The isolation valve is re-
quired for priming, regulation of flow, and for inspection and maintenance of pump. The check
valve prevents pump or seal damage due to reverse flow through the pump when the driver is
turned off.
2.
lncreasers, if used, should be placed between pump and check valves.
3.6 Piping
3196CC Installation, Operation and Maintenance Instructions
23
