Mody Pumps MS 121 - Manual (Page 10)

GENERAL OVERHAUL AND OIL CHECK.
DIS-ASSEMBLY(REFER DRG.NO.MS/860/00 AT END OF MANUAL)
• IT IS MANDATORY THAT ALL "O" RINGS BE REPLACED WHENEVER A PUMP IS OVERHAULED
OR DISMANTLED. UNDER NO CIRCUMSTANCES SHOULD OLD "O" RINGS BE USED, EVEN IF
THEY SEEM O.K. BE CAREFUL NOT TO SCRATCH SEALING SURFACES. ALWAYS GREASE NEW
“O” RINGS BEFORE INSTALLATION.
• ALWAYS ISOLATE THE UNIT FROM ELECTRICAL POWER BEFORE ATTEMPTING ANY
OVERHAUL.
• THE TRANSPORTABLE VERSION IS SUPPLIED WITH A PUMP BASE (63). REMOVE BASE
BEFORE ANY FURTHER DIS – ASSEMBLY. THE PERMANENT INSTALLATION VERSION IS
SUPPLIED WITH A SLIDING BRACKET FIXED ON THE VOLUTE OF THE PUMP. LAY THE
PUMP ON IT’S SIDE ON A BENCH OR OVER TWO SUPPORTS. TURN THE PUMP SO THAT THE
OIL HOLE FACES DOWNWARDS. USING AN ALLEN KEY UNSCREW OIL PLUG (33) TO DRAIN
OIL FROM THE SEAL CHAMBER. IT IS EASIER TO DRAIN THE OIL IF THE OTHER OIL
HOLE CAP SCREW IS ALSO REMOVED. BE CAREFUL. IF THE SEAL HAS LEAKED, THE OIL
CASING MAY BE UNDER PRESSURE. HOLD A RAG OVER THE OIL PLUG TO PREVENT
SPLATTER.
• UNSCREW CAP SCREW (26) AND REMOVE PUMP IMPELLER (24) FROM VOLUTE (22).
REMOVE LOCKING SPACER (25) AND SLIDE IMPELLER OF THE MOTOR SHAFT. IF THE
IMPELLER IS SLIGHTLY TIGHT USE A WOODEN MALLET TO TAP THE SAME OFF THE
SHAFT. REMOVE KEY (29) AND KEEP ASIDE CAREFULLY.
• THE LOWER MECHANICAL SEAL IS NOW IN VIEW. REMOVE TRIMMING SPACER (S)(30).
USING A NOSE/CIRCLIP PLIER REMOVE CIRCLIP (31). THE MECH. SEAL ASSEMBLY CAN
NOW BE REMOVED FROM THE SHAFT BY HAND. BE VERY CAREFUL WITH THE SEALING
SURFACES SO THAT THEY DO NOT SUFFER DAMAGE OR GET SCRATCHED IN ANY WAY.
LEAVE THE SEAL SEAT IN THE SEAL HOUSING.
• UNSCREW NUTS (16) HOLDING THE VOLUTE AGAINST THE STATOR CASING AND REMOVE
VOLUTE USING A WOODEN MALLET TO TAP OFF THE SAME. THE UPPER MECH. SEAL IS
NOW IN VIEW. REMOVE THE SEAL IN EXACTLY THE SAME MANNER AS THE LOWER MECH.
SEAL.
• UNSCREW HEX HD BOLTS (21) HOLDING THE LOWER BEARING BRACKET (20) AGAINST THE
STATOR CASING. THE COMPLETE ROTOR ASSEMBLY WITH LOWER BEARING BRACKET AND
LOWER BEARINGS CAN BE PULLED OUT FROM THE STATOR ASSEMBLY. THE LOWER BEARING
BRACKET CAN BE REMOVED FROM THE ROTOR BY REMOVING THE BEARING COVER. THE
BEARING CAN NOW BE EXAMINED.
• UNSCREW HEX NUT (4) HOLDING THE PUMP COVER (1) AND PRY OUT THE SAME. REMOVE
THE WIRE CONNECTORS (45 & 49) TO SEPARATE THE POWER CABLE FROM THE MOTOR
LEADS. THE WIRE CONNECTORS CAN BE UNSCREWED COUNTER CLOCKWISE TO RELEASE THE
SAME. UNSCREW NUT FOR GROMMET (42) AND REMOVE RUBBER GROMMET (41). REMOVE
HEX HD BOLT (44) AND PRY OUT UPPER BEARING BRACKET(7).
• THE STATOR IS NOW AVAILABLE FOR ELECTRICAL CHECKS, IF ANY ARE REQUIRED. WE
RECOMMEND MEASURING LINE TO LINE RESISTANCE BETWEEN THE THREE POWER LEGS, A
MEGGING TEST AND IF AVAILABLE A HIGH POT.
• REMOVE THE CABLE GLAND ASSEMBLY (50) BY TAKING OFF THE HEX NUTS (4). USING
TWO SCREWDRIVERS GENTLY PLY OUT THE CABLE GLAND BASE (53). EXAMINE THE CABLE
LEAD GROMMET (54) AND THE CABLE GROMMET (51). REMOVE THE WIRE NUTS (45) AND
UNSCREW THE EARTHING SCREW (49).