NOTICE:
If the impeller was supplied without wear rings and excessive wear has occurred, then wear
rings can be fitted in the field. The impeller must then be remachined. Contact your local ITT
representative for details.
Casing joint gasket
Inspect the parting gaskets (331). If they are torn or otherwise damaged, then cut a new gasket of 0.8
mm | 1/32 in. non-asbestos material using the recommendations below. Use the upper half of the casing
as a template. Strike the face with a soft-face hammer. This will cut the gasket against the edge of the
casing. The gasket must cover the entire surface of the parting flange, especially around the wear ring
locks and stuffing box. Otherwise, internal leakage from high to low pressure zones in the pump will oc-
cur.
The following gasket materials are recommended if pre-cut replacement gaskets are not available:
•
JM - 961
•
Durable - Durlon
•
Garlock Blue Guard 3000
•
Armstrong - N8090
•
Rodgers - D7031
Shaft
Check the shaft (122) for runout to make sure that it is not bent. Straighten or replace the shaft as neces-
sary. Bearing seats must be in perfect condition. Check keyways for burrs or foreign matter.
Impeller
Check the impeller (101). Replace the impeller if any of the following conditions exist:
•
Excessive erosion, especially on inlet vanes
•
Deterioration of the gasket mating surface to the point that the gasket (428) cannot seal properly
•
Excessive erosion of surfaces
If the impeller diameter needs to be cut, then make sure that it is dynamically-balanced. Grind the out-
side of the shrouds near the periphery in order to correct imbalance.
Shaft sleeve
The sleeve (126) surface in the stuffing box area must be smooth and free of grooves. If there are
grooves, replace the shaft sleeve. The O-ring groove in the end of the sleeve nut must be in good condi-
tion. The impeller end of the sleeve must be in good condition to ensure that the gasket (428) will seal
properly. The original diametric clearance between the shaft sleeve and the stuffing box bushing is 0.76–
0.86 mm | 0.030–0.034". If this clearance has increased to more than 1.27–1.5 mm | 0.050–0.060", then
the sleeve, and possibly the stuffing box bushing, must be replaced.
Bearings
Check ball bearings (112 and 168) for visible wear. Slowly turn the races and look for pits or worn areas
on the balls or raceways.
Hold the inner race and spin the outer race. If there are rasping noises or the bearing catches or binds,
then replace the bearing. If any wear on the race is apparent, then replace the bearing.
Replace ball bearings that are worn, loose, rough, or noisy when rotated.
6.6 Preassembly inspections
66
Model 3410 Installation, Operation, and Maintenance Manual
