Goulds Pumps XHD - IOM - Manual (Page 45)

Commissioning, Startup, Operation, and Shutdown
Impeller clearance (total travel)
Pump size Impeller Maximum Total Impeller Minimum Total
Clearance inches (mm) Clearance inches (mm)
XHD80 0.37 (9.4) 0.10 (2.6)
XHD125 0.39 (9.8) 0.10 (2.6)
XHD150 0.43 (10.8) 0.13 (3.3)
XHD200 0.47 (11.8) 0.16 (4.1)
XHD250 0.47 (11.9) 0.16 (4.0)
XHD300 0.51 (12.8) 0.18 (4.6)
Impeller-clearance setting
Importance of a proper impeller clearance
A proper impeller clearance ensures that the pump runs at high performance.
WARNING:
• The pump should be run for a period of 15 minutes to verify the impeller is properly tightened onto
the shaft. In addition to verifying the impeller is properly tightened, it is necessary to verify that the
bearing frame adjustment plate bolts (352G) and nuts (427D) are properly secured and tight. Failure
to check that the impeller is tight and the bearing frame adjustment plate bolts and nuts are properly
tightened can result in the rotating element shifting during operation.
• The impeller clearance setting procedure must be followed. Improperly setting the clearance or not
following any of the proper procedures can result in sparks, unexpected heat generation, and
equipment damage.
The front clearance is set at .51 mm (0.020 in) at the factory but could change due to piping
attachment during installation. A change in pump performance may be noted over time by a
drop in head or flow or an increase in power required.
Table 5: Impeller clearance methods
The XHD and XHD Value Option models have different methods of setting the impeller clearance.
Pump Model Method
XHD The impeller clearance is set by measuring the gap between the rear shroud of the
impeller and the casing volute liner, and measuring the gap between the front of the
impeller and the suction seal ring clearance.
Skip to the "Set Impeller to Suction seal Ring Clearance Dial Dial Indicator Method -
XHD" step.
After impeller rear clearance has been set on the XHD, the suction seal ring
clearance must also be set.
XHD Value Option The impeller clearance is set by measuring the gap between the front of the impeller
and the suction side liner. Use the "Set the impeller clearance dial indicator method
- XHD Value Option" step.
XHD Installation, Operation, and Maintenance Manual 43