Flint & Walling Centrifugal Packages - end suction centrifugal pumps User Manual

Page 5

95 North Oak Street • Kendallville, IN 46755

completely filled with liquid. This priming can be
accomplished by any of the following methods.

2. When the liquid supply level is above the center

line of the pump, it is primed by opening the
suction and discharge valves. The inflowing liquid
will displace the air and fill the suction line, pump
casing, and discharge line up to the level of supply.

3. Where the pump is operating with suction lift and

the suction line is equipped with a foot valve, the
system is filled with liquid by filling through the
discharge piping.

STARTING
1. Follow the steps below in the order indicated to start

pump:

• Close gate valve in discharge line.
• Open gate valve in suction line.
• Turn on power to pump motor.
2. When pump is operating at full speed, immediately

open the discharge gate valve slowly.

3. If the pump does not prime properly, or loses it

prime during start-up it should be shut-down and
the condition corrected before the procedure is
repeated.

NOTE: The gate valve in the discharge line should
always be closed when the pumps is started. The
excessive current required by the motor to start under
full load will in time cause motor trouble. A centrifugal
pump primed and operated at full speed with the
discharge gate valve closed usually requires much less
power than when it is operating at its rated capacity
and head with the discharge gate valve open.
OPERATING CHECKS
1. After initial start-up:
• Check the pump and piping to assure there are no

leaks.

• Check and record pressure gauge readings for

future reference.

• Check and record voltage, amperage per phase.
STOPPING PUMP
1. When stopping pump always close the discharge

valve first.

2. Pump should never run for any length of time with

both suction and discharge valves closed due to
danger of building up pressures and temperatures.

MAINTENANCE
LUBRICATION
1. The pump and motor requires no lubrication. The

ball bearings of the motor have been greased at the
factory. Under normal operating conditions they
should require no further greasing.

FREEZING
1. Drain the entire system if there is danger of freezing.

A drain plug is provided at the bottom of the pump
case for this purpose.

ROTARY SHAFT SEAL
1. The mechanical shaft seal should be replaced if

water is noticed around the motor shaft. Remove
case and impeller and, using two screw drivers to
pry on each side, remove seal stationary seat. Clean
seat area of frame, install new stationary seat with
ceramic surface facing out and slide new rotating
element over shaft sleeve with hard carbon surface
against ceramic seat. Be sure to keep all surfaces
clean. Lubricating seal parts with water will help the
installation of the seal. Reinstall impeller and pump
case.

CAUTION: Make certain that the power supply is

disconnected before attempting to service the unit!

Failure to do so could result in personal injury or fatal

electrical shock.

MOTOR
1. Keep motor clean and dry. It is drip-proof when

installed horizontally and the windings are protected
from excess humidity, but extreme conditions
should be avoided when possible. If motor fails to
run, be sure power is on, all switches or electrical
controls are closed, fuses are in order and all
electrical connection are tight. (Motor must be
repaired by Authorized Repair Station under terms
of guarantee.)

FAILURE TO PUMP
1. If the motor runs, but no water is pumped, be

sure pump is primed, that there are no air leaks in
suction piping, that all gate valves are open and all
check valves operate.

NET POSITIVE SUCTION HEAD (NPSH)
1. NPSH combines all of the factors limiting the

suction side of a pump; internal pump losses,
static suction lift, friction losses, vapor pressure
and atmospheric conditions. It is important
to differentiate between REQUIRED NPSH and
AVAILABLE NPSH.

NPSH REQUIRED
1. REQUIRED NPSH is a factor designed into a pump

and measurable in the test laboratory by the
manufacturer. Testing facilities can determine losses
in the suction piping, static lift and barometric
pressures.

NPSH AVAILABLE
1. The term for providing sufficient pressure on the

suction, at the impeller eye, to prevent “boiling”
is known as NPSH AVAILABLE. It is a function of
the pumping system and consists of pressure on
the liquid at its source, the elevation of the liquid
with respect to the impeller centerline, losses in the
suction piping and vapor pressure of the liquid.

2. If the available NPSH is not equal to, or greater than

that required by the pump, it must be increased.
This is usually done by increasing the static head,
Hz.