Xylem P5002169B Series VSX VSH, VSC, AND VSCS - Manual (Page 23)

20
stuffing box. In all cases, however, we
recommend an inspection of the packing
before pump is started.
A soft, well-lubricated packing reduces
stuffing box resistance and prevents
excessive wear on the shaft sleeve. Standard
packing may be purchased through you local
Bell & Gossett representative.
When a pump with packing is first started it is
advisable to have the packing slightly loose
without causing an air leak. As the pump runs
in, gradually tighten the gland bolts evenly.
The gland should never be drawn to the point
where packing is compressed too tightly and
no leakage occurs. This will cause the
packing to burn, score the shaft sleeve and
prevent liquid from circulating through the
stuffing box cooling the packing. The stuffing
box is improperly packed or adjusted if friction
in the box prevents turning the rotating
element by hand. A properly operated stuffing
box should run lukewarm with a slow drip of
sealing liquid. After the pump has been in
operation for some time, and the packing has
been completely run-in, drippage from the
stuffing box should be at least 40 to 60 drops
per minute. This will indicate proper packing
and shaft sleeve lubrication and cooling.
NOTE: Eccentric run-out of the shaft or
sleeve through the packing could result in
excess leakage. Correcting this defect is very
important.
Packing should be checked frequently and
replaced as service indicates; it is impossible
to give any exact predictions. A packing tool
should be used to remove all old packing
from the stuffing box. Never reuse worn
packing or merely add some new rings. Make
sure the stuffing box is thoroughly cleaned
before installing new packing. Also check the
condition of the sleeve for possible wear.
Make replacements where necessary.
New packing (non-asbestos) should be
placed carefully into the stuffing box. If
molded rings are used, the rings should be
opened sideways and the joints pushed into
the stuffing box first. The rings are installed
one at a time, each ring seated firmly and the
joints staggered at about a 90° rotation from
each preceding joint.
If coil packing is used, cut one ring to
accurate size with either a butt or mitered
joint. An accurately cut butt joint is superior to
a poor fitting mitered joint. Fit the ring over
the sleeve to ensure proper length. Then
remove and cut all other rings to the first
sample. When the rings are placed around
the sleeve a tight joint should be formed.
Place the first ring in the bottom of the
stuffing box. Then install each succeeding
ring, staggering the joints as described
above, making sure each ring is firmly
seated.
Make sure the lantern ring is properly located
in the stuffing box under the sealing water
inlet. The function of the lantern ring is to
establish a liquid seal around the shaft,
prevent leakage of air through the stuffing
box and lubricate the packing. If it is not
properly located it serves no purpose.
MAINTENANCE OF FLOOD DAMAGED PUMPS
WARNING: Unexpected Startup Hazard
Disconnect and lockout power before servicing.
Failure to follow these instructions could result in
serious personal injury or death, or property
damage.
WARNING: Electrical Shock Hazard
Electrical connections to be made by a qualified
electrician in accordance will all applicable codes,
ordinances, and good practices.
Failure to follow these instructions could result in
serious personal injury or death, or property
damage.
Replace bearings and grease if the pump has
been in a flooded condition. The motor should be
evaluated by a qualified motor shop before being
put back into service. Mechanical seals, stuff
boxes, and their packing rings should be cleaned
and inspected. Replace if needed. Couplings that
require lubrication should be replaced.