Finish Thompson SP11/15 SERIES SELF-PRIMING - Manual (Page 8)

Section II - Installation
Mounting -
Pump foot should be securely
fastened to a solid foundation. If
the pump was received with plastic
shipping shims, it is possible to
use these as additional support
for the motor feet (though not
required).
NOTE: B5 pumps with
100/112 frame do not include a
pump foot.
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
calculated 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 25 feet (7.6 meters).
NOTE: Maximum suction lift is reduced by 1.13 feet (.34 meters) for every 1,000 feet (304 meters) of altitude.
• 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 performance.
The suction piping should be level or slope slightly upward to the pump.
• The suction pipe should be 1 1/2” (38 mm). Larger suction piping will affect priming ability. Smaller piping affects
NPSH available and pump performance.
• Provide for adequate suction submergence. Excessive submergence will reduce pump performance.
• The end of the pipe should be at least 3” (7.6 cm) above the bottom of the suction tank.
• If a strainer is used, it 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 regulat-
ing 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.
SP Piping Diagram
8