Mody Pumps G 806 T - Manual (Page 7)

GALVANIC CORROSION PROTECTION (FOR SEA-WATER DUTY PUMPS ONLY)
THE PARTS OF THE "MODY" SUBMERSIBLE PUMP THAT ARE IN CONTACT WITH SEA- WATER
ARE PRIMARILY OF STAINLESS STEEL AND ALUMINUM. AS SEA-WATER IS AN ELECTROLYTE
THE PROBLEM OF GALVANIC CORROSION EXISTS DUE TO THE DIFFERENT ELECTRIC
POTENTIALS OF THE MATERIALS IN FLOWING SEA-WATER. TO PREVENT THIS, THE PUMPS
ARE EQUIPPED WITH ZINC ANODES FIXED ON THE OUTER CASING AND DIFFUSER. ZINC,
BEING THE LESS "NOBLE" METAL (MORE NEGATIVE POTENTIAL) GETS CORRODED THUS
PREVENTING CORROSION OF ALUMINUM AND STEEL. IT IS HOWEVER NECESSARY TO INSPECT
THE CONDITION OF THE REPLACEABLE ANODES PERIODICALLY AND REPLACE WHENEVER
NECESSARY. (TYPICALLY INSPECTION ONCE A YEAR SHOULD SUFFICE)
NON REPAIRABLE ITEMS
1. ALL "O" RINGS TO BE REPLACED WHENEVER PARTS ARE DISMANTLED.
2. SEAL ELASTOMER PARTS SHOULD NEVER BE RE-USED AFTER DIS-ASSEMBLY.
3. DO NOT REFILL BEARING GREASE. NEW BEARINGS MUST BE INSTALLED WITH SPECIAL
HIGH TEMPERATURE GREASE.
ELECTRICAL INFORMATION .
MOTORS ARE DESIGNED TO OPERATE ON SINGLE VOLTAGE AND FREQUENCY. MAXIMUM
DEVIATION IN VOLTAGE ALLOWED IS +/-6% AND FREQUENCY +/-3%. CHECK NAME PLATE FOR
OPERATING VOLTAGE AND FREQUENCY.
DISMANTLING AND OVERHAULING.
GENERAL OVERHAUL AND OIL CHECK. (REF. DRGS. NO.DW/144/00 (SHEET 1 & 2)
1. ALWAYS REPLACE O-RINGS WITH NEW ONES WHENEVER DISMANTLING AND RE-ASSEMBLING
A PUMP. NEVER RE-USE OLD O-RINGS.
2. ALWAYS ISOLATE THE UNIT BEFORE REMOVING THE CABLE GLAND (59). BE CAREFUL
WITH O-RINGS (67,68,69) AND SEALING SURFACES. PROTECT THE CHAMBER AGAINST RAIN
AND MOISTURE.
3. DISCONNECT STATOR LEADS. SNIP OFF LEAD WIRE CONNECTORS AND UNSCREW EARTHING
SCREW (45). LOOSEN SCREWS (46), REMOVE CABLE GROMMET (61) AND CABLE LEAD
GROMMET (70). CLEAN THE SEALING SURFACES CAREFULLY AND GREASE THE NEW O-RINGS
BEFORE FITTING THE SAME. DO NOT USE THE OLD O-RINGS.
4. LOOSEN HX. BOLTS AND LOCK WASHERS (28,29) AND REMOVE BASE PLATE (27),
STRAINER (26), DIFFUSER CENTER (23), AND DIFFUSER HOLDER (22). PRY OUT DIFFUSER
RING (21) FROM OUTER CASING (13). THE DRAWING SHOWS THESE DETAILS. CHECK BY
HAND THAT THE ROTOR SHAFT IS NOT JAMMED.
5. PLACE THE PUMP ON THE BOTTOM STUDS (19). TAP THE OUTER CASING (13) WITH
NYLON HAMMERS/MALLET TILL IT LOOSENS FROM THE TOP BRACKET (7). SEPARATE THE
OUTER CASING FROM THE TOP BRACKET BY EMPLOYING TWO SCREW DRIVERS AS LEVERS AND
PUSH THE OUTER CASING DOWNWARDS TILL IT STANDS ON THE FLOOR. LIFT THE UNIT BY
THE EYEBOLTS (4) CLEAR OFF THE OUTER CASING.