Xylem IM158 R04 Model SMVT - Manual (Page 17)

SMVT Installation, Operation and Maintenance Manual 15
Figure 8: Piping Elbows
2. Use suction pipe that is one or two sizes larger than the pump suction with a reducer at the
suction. Suction piping should never be smaller diameter than the pump suction.
3. Reducers should be eccentric at the pump suction with sloping side down and horizontal
side at the top (Reference Figure 9).
Figure 9: Eccentric Reducer
4. Suction strainers, when used, must have a net “free area” of at least three times the suction
pipe area.
5. Separate suction lines are recommended when more than one pump is operating from the
same source or supply.
Suction Lift Conditions
If pump is to be installed above the liquid source, the following MUST be provided:
1. No part of the suction piping can be above the pump suction (to avoid air pockets).
2. Suction piping must slope upwards to the pump on any horizontal pipe sections.
3. All joints MUST be airtight.
4. A means of maintaining prime during intermittent duty, such as a foot valve, must be
provided.
5. The suction strainer or suction bell MUST be at least three times the diameter of the
suction.
6. Ensure that the size and minimum submergence over the suction inlet is sufficient to prevent
air from entering the pump through a suction vortex. See typical intake piping arrangements
in Figures 10-13.
Installation (continued)