WDM AG Series Operation Manual page 8

Operation Manual.
The suction line must not have holes. The slightest air
leak in the suction line can prevent the pump from priming.
To insure an air tight joint, use pipe thread compound in
all threaded connections in the suction line. . Suction
flanges should also be pulled up tight to prevent air leaks.
Negative Suction
Shut-off Valve
Priming plug
8 8
Union
Piping Support
Foot Valve & Strainer
Check Valve
Union