Crane Crown B12 Series, Installation And Operation Manual

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3. In cold weather operation, the pump will not freeze as
long as it is running. However, it may freeze if it is not drained
while standing idle. To drain the pump, remove the drain plug
at the bottom of the pump case and rotate the impeller at
least once to assure removal of all the water.
4. The discharge of a self priming centrifugal pump may be
closed briefl y without damaging the pump. However, the wa-
ter will soon heat up and this can damage to the pump seal.
5. It is not desirable to run the pump without liquid in the
pump case. If the pump must be run in order to check the
operation of the engine or motor, fi ll the case with suffi cient
water to keep the rotating seal wet. This will eliminate dam-
age to the seal and other pump parts.
6. If the pump has been idle for some time, the impeller may
appear to be stuck or locked in place. This is usually caused
by a fi lm of rust or dirt between the impeller and volute. A little
extra force on the crank may break it loose. If not, the pump
must be dismantled.
SECTION E: MAINTENANCE RECOMMENDATIONS:
E-1) Seal Lubrication:
A self-feeding lubricator is provided to supply grease to the
shaft seal of the pump. The grease cup is empty when the
wing nut, positioned at the outer end of the threaded plunger
shaft, recedes to the cap of the grease cup. To refi ll the
grease cup, rotate the wing nut clockwise as far as it will
go, attach a zerk gun to the zerk fi tting, then fi ll until grease
oozes from the relief hole on the side of the cup. For opera-
tion, return the wing nut to the end of the plunger. Never
force the plunger into the grease cup as this can cause seal
failures. (See Fig. 1)
A #1 grease is normally recommended. However, where high
ambient temperatures are encountered, such as in direct
sunlight, a #2 grease can be used. Use a water resistant,
nonfi berous grease. Lithium base greases are excellent and
molydisulphide is acceptable. Normally, the sodium soap
base greases are the only non-water resistant types that are
not acceptable for mechanical seal lubrication.
If the pump is inoperative for a long period of time, or appears
not to use any grease, remove and clean the cup thoroughly.
Caked grease in the cup can create a problem of
non-lubrication to the seal. Under normal conditions, a grease
cup full of grease will last three to four months. If a grease
seal requires grease every day, and it is not leaking past the
outer lip seal it indicates that the seal is wearing out. The
internal pressure of the pump will often force the cup plunger
out when the seal leaks badly.
E-2) Shaft Seal Replacement:
All parts of the pump are easily dismantled by simply
removing nuts and screws. Rotating parts of the shaft seal
grip the shaft by friction and may be frozen to the shaft
through long usage.
If the mechanical shaft seal is not leaking and it is necessary
to dismantle part of the pump for inspection or cleaning
DO
NOT disturb the shaft seal other than its spring if the impeller
is removed. Once a shaft seal has been in operation it cannot
be removed and replaced without leaking.
CAUTION ! - Handle parts with extreme care.
Do not scratch or mar lapped surfaces.
It is recommended to remove the pump side from the support
bracket. After the pump has been disassembled make sure
that the shaft and seat areas in the pump side are as clean
as possible. The shaft must not be sharp, but neatly rounded
and polished to a 1/32” radius. This radius and the shaft, on
which the rubber bellows grips, must be polished with 180 to
240 grit emery cloth. The seal will install relatively easy if the
shaft is properly polished.
Install the seat assembly (1 and 2 or 1A and 2A, see Figure
2) in pump side adapter (12) using SAE# 10 oil on the rubber
parts. They may install easier by fi rst inserting the rubber part
and then sliding the seat part into the rubber. All of this must
be done with the fi ngers only.
FIGURE 1