5.2
Pipes
5.2.1
Pipe sizing
Suction lines which are too long have significant disadvantages:
•
Higher resistance which results in reduced suction
performance and a higher risk of cavitation.
•
Longer priming time, up to 12 minutes.
The dimensions which are specified in the pump data sheet only
apply to a pipe length of maximum 5 m.
For longer pipes, losses due to pipe friction must be taken into
account.
Size pipes according to the data in the tables. See pump
data sheet.
5.2.2
Laying pipes
Keep the suction and pressure lines as short and straight as
possible.
Avoid sudden changes to the cross-section and direction.
If possible, lay the suction line below the water level.
Lay the suction line as follows to prevent air pockets from
forming:
– For intake mode: continuously falling.
– For suction operation mode: continuously rising.
If the pump is installed above the water level, install a foot
valve in the suction line (required for non-self-priming pumps,
recommended for self-priming pumps). Thus, the suction line
cannot drain when the pump isn't working and the priming
time remains short, for example after cleaning the basket.
If clogging is possible, for example with straw or grass, install
a filter in the intake or the suction line.
Depending on the type of pump and system, install a non-
return valve as necessary.
Install a shut-off valve in both the suction and pressure lines.
Avoid valves which close suddenly. Install a shock absorber
or air vessel if necessary.
NOTICE
If the suction line leaks, the pump will prime poorly or not at all.
08|2018
Installation
EN 17