d) A foot valve should only be used if necessary for priming, or, if the pump is to be used on inter-
mittent service and is required to hold its prime.
e) Suction strainers when used should have a net free area of at least three times the suction pipe
area.
3.
Installations With Pump Below Source of Supply - Suction Head or Flooded Suction:
a) A gate valve should be installed in the suction line to permit closing the line for pump inspection
and maintenance.
b) Keep suction pipe free from air pockets.
• Piping should be level or slope gradually downward from the source of supply.
• No portion of the piping should extend below the pump suction flange.
c)
The size of entrance from the supply should be no smaller than the suction pipe.
d) The suction pipe should be below the liquid surface at the source of supply as shown in
2.5 Install suction piping
16
3405-3406-3416 Installation, Operation and Maintenance Instructions