Finish Thompson SP10 SERIES SELF-PRIMING - Manual (Page 7)

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CAUTION: The NPSH available to the pump must be
greater than the NPSH required. The amount of lift,
frictional pipe loss, and vapor pressure must be calcu-
lated into the application. NPSH available should be 2
feet (.6 meters) greater than NPSH required.
• Total suction lift including pipe friction loss and
corrections for specific gravity must not exceed value
shown in chart below.
SP10 Maximum Lift Chart
1” (25.4 mm) Suction
Piping
1.5” (38.1 mm) Suction
Piping
Impeller Diameter Max. Lift
@ 3450 rpm
Max. Lift
@ 2900 rpm
Max. Lift
@ 3450 rpm
Max. Lift
@ 2900 rpm
4.18” (106.2 mm) 25’ (7.6 M) 25’ (7.6 M) 25’ (7.6 M) 25’ (7.6 M)
4.00” (101.6 mm) 25’ (7.6 M) 25’ (7.6 M) 25’ (7.6 M) 20’ (6.1 M)
3.75” (95.3 mm) 20’ (6.1 M) 20’ (6.1 M) 20’ (6.1 M) 15’ (4.6 M)
3.5” (88.9 mm) 20’ (6.1 M) 15’ (4.6 M) 15’ (4.6 M) 10 (3.1 M)
3.25” (82.6 mm) 15’ (4.6 M) 10 (3.1 M) 15’ (4.6 M) 10 (3.1 M)
3” (76.2 mm) 10’ (3.1 M) 5’ (1.5 M) 10’ (3.1 M) 5’ (1.5 M)
• Install the pump as close to the suction source as
possible.
• SP Series pumps are designed to operate in a horizontal
position only with discharge on the top.
• SP Series pumps self-priming capability is due to its
ability to create a vacuum in the suction piping. The
suction piping MUST be airtight at fittings and
connections.
• Support the piping independently near the pump to
eliminate any strain on the pump casing. In addition,
the piping should be aligned to avoid placing stress on
the pump casing.
• The suction side of the pump should be as straight and
short as possible to minimize pipe friction.
• The suction line should not have any high spots. This
can create air pockets that can reduce pump perfor-
mance. The suction piping should be level or slope
slightly upward to the pump.
• The suction pipe should be 1” (25.4 mm) or 1½” (38
mm). Larger suction piping will affect priming ability.
Smaller piping affects NPSH available and pump per-
formance. See SP10 performance curve book or on-line
at www.finishthompson.com.
• Provide for adequate suction submergence. Excessive
submergence will reduce pump performance.
• The end of the pipe should be at least 2” (5.08 cm) for
1” pipe & 3” (7.6 cm) for 1½” pipe above the bottom
of the suction tank.
• If debris is in the suction tank, a strainer can be in-
stalled to help prevent foreign matter from entering
the pump. The strainer must be periodically cleaned to
prevent restriction.
• It is recommended that a vacuum/pressure gage be
installed in the suction piping.
• For faster priming on installations with high lift, a foot
valve is recommended.
• Check and control valves (if used) should be installed
on the discharge line. The control valve is used for
regulating flow. Isolation valves on the suction and
discharge are used to make the pump accessible for
maintenance. The check valve helps protect the pump
against damage from water hammer. This is particularly
important when the static discharge head is high.
NOTE: If a check valve is used in the discharge line, it
must be placed at a distance at least equal to the maxi-
mum suction lift from the pump. If this cannot be done,
an air vent must be provided in the discharge line.
• If flexible hose is preferred over pipe, use a vacuum
rated reinforced hose for the proper temperature, pres-
sure and is chemically resistant against the fluid being
pumped.
• The suction valve must be completely open to avoid
restricting the suction flow.
• When installing pumps with flanges, we recommend
use of low seating stress gaskets such as Gore-Tex or
Gylon (expanded PTFE).
• It is advisable to install a flush system in the piping to
allow the pump to be flushed before the pump is re-
moved from service.
NOTE: The pump is provided with a 1/2” BSPP drain
in the impeller housing.
• A “tee” can be installed in the discharge piping as an
alternative location for filling the housing with fluid
before pump operation.
• “Filling” is defined as filling the housing with 0.6 US
gallon / 77 oz. (2.7 liters) of liquid
• “Priming” is defined as evacuating all the air from the
suction piping/pump and replacing it with fluid. See
Priming chart on next page.
NOTE Maximum suction lift is reduced by 1.13 feet
(.34 meters) for every 1,000 feet (304 meeters) of
altitude.