Trillium 8-WSP, Installation, Operation And Maintenance Instructions, Page: 45 / 68

WSP™
DATA SHEET WSP™ SELF-PRIMER PUMPS WSP-D300_8
Rev. 3 01/09/20
© 2019 The Factory
45
F. DISCHARGE LINES
1. Siphoning
Avoid ending the discharge line lower than the liquid being pumped
unless a siphon breaker is in use. Without a siphon breaker installed,
siphoning may damage the pump.
2. Valves
When using a discharge line throttling valve, it
must
be the same size
as the largest pipe to reduce friction loss. Do
not
install a throttling
value in the suction line.
If using high discharge heads, Weir Specialty Pumps suggests a
throttling valve coupled with a system check valve in the discharge
line. When the pump is stopped, this helps ensure the pump is safe
from reverse rotation and extreme shock pressure.
IN HIGH DISCHARGE HEAD APPLICATIONS THE DISCHARGE THROTTLING VALVE
MUST BE GRADUALLY CLOSED BEFORE THE PUMP IS STOPPED.
3. Bypass Lines
When priming, air from the suction line
must
be vented on the
discharge side to the outside since self-priming pumps are
not
air
compressors. Should the discharge line be open, this air will vent
through the discharge.
When a discharge line check valve is installed, the pump discharge
side
must be
open to outside pressure. The discharge may either be
through a bypass line or through a WSP™ ARV that has been
installed between the pump discharge and the check valves.
Self-priming centrifugal pumps cannot prime when there is enough
interior liquid pressing against the discharge check valve to keep it
closed.
NOTE:
Any bypass line must be correctly sized to avoid compromising the pump’s
discharge capacity. A bypass line must have a minimum diameter of 1 inch
to reduce chances of plugging.