Appendix H—Aboveground Installation/Piping Instructions
H. Aboveground Installation/Piping Instructions
3
1
5
6
2
4
No!
Yes!
No!
Yes!
No!
Yes!
Don’t use restricted inlet line!
Concentric Reducer
Eccentric Reducer
Use inlet line larger than
pump suction nozzle. Same
size nozzle OK on short runs.
Don’t allow bypass line to
have low spot.
Keep return line level or go up
toward tank!
Pressure drop caused by restriction in suction line will cause vaporization and cavitation.
An eccentric reducer should always be used when reducing into any pump inlet where vapor might be encountered
in the pumpage. The flat upper portion of the reducer prevents an accumulation of vapor that could interfere with
pumping action.
Low spots in bypass line can collect liquid which prevents normal vapor passage for priming purposes just like the P
trap in the drain of a kitchen sink. This is not a problem for bypass lines where vapor elimination is not required.
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