Overhaul Maintenance; Disassembling The Pump - Wilo MISO 25-125 Manual

9.2 Overhaul maintenance

9.2.1 General information
After a long period of service, wear will occur in parts of
the pump, necessitating the renewal of a few
components. Logbook records will indicate wear as
gradual deterioration of performance is noticed. Once this
is known, pumps should be taken for overhaul. It is
recommended that yearly stripping & checking of wear &
tear and clearances should be done and overhauling where
required.
If related pair of components show a marked degree of
wear in relation to the rest of the unit, then it may be
sufficient to renew only the heavily worn components. If
the wear is uniform throughout the pump, then all
wearable components may require renewal.
Measurements should be taken and recorded of all
wearable components at the first, and every subsequent
overhaul period. Reference to these records will enable an
accurate assessment of the rate of wear to be made, and
a reasonably accurate forecast regarding when a particular
component may require renewal can be made.
NOTE:
The figures given in the table (Technical Data Pg. No.12)
above are only valid if the wear rings and the impeller are
made with in the same materials of low galling tendencies.

9.3 Disassembling the pump

Exploded view of Gland Pack Pump
Installation and operating instructions WILO Mather and Platt –MISO / PISO Pumps
For materials with higher galling tendencies (AISI 304/316
etc...), higher clearance is provided (0.125 mm to be added to
given values).
Information regarding original design dimensions and
clearances is furnished in data sheet. Any other information, if
needed, can be requested from Service Department, WILO
Mather and Platt. Such request must quote name plate
number and type of the pump in question.
The parts most likely to be affected are:
• Impeller
• Mechanical seal
• Neck Rings
• Sleeves
• Stuffing Box Bush
• Bearings
• Coupling Bushes/ membrane set
Before commencing dismantling operations, ensure that the
following tools and tackles are available:
• A crane / chain pulley block suitable for handling the weight
of pumping unit.
• A selection of ring and open-ended spanners in British and
Metric sizes.
• Eyebolts in Metric sizes.
• Cotton rope, wire rope and slings.
• Hardwood and metal packing blocks.
• Miscellaneous tools including a set of Allen keys, drills, pin
drivers, files etc.
• Extractor / puller for bearing and coupling.
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