Mitsubishi Electric City Multi PURY-EM200YNW-A1, Service Handbook

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[8-15 Main-HBC Maintenance Instructions ]
144
- chapter 8 BS_08_L
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8-15-9 Disassembling the Pump and Replacing the Mechanical Seal (HBC)
1. Breakdown diagram of the pump
2. Cautionary notes for replacement
(1) Points for attention when replacing mechanical seals
1) The mechanical seal should be handled gently to prevent damage to the seal, and the mechanical seal and pump cavity
should be cleaned before installation.
2) Mechanical seals shall be kept clean and shall not be contaminated with stains, impurities, dust or dirt.
3) During the installation of the mechanical seal, the sealing element shall not be struck directly with a tool to prevent damage
to the sealing element.
(2) Points for attention when replacing plug components
1) Ensure that the 0-ring is not distorted and overstretched when installing the plug assembly.
2) Plug components should be kept clean and should not be contaminated with stains, impurities, dust or dirt.
3) Check the installation surface for no burrs, flying edges, impurities, dust and other defects and scratches before installation.
4) Do not reuse the plug assembly.
5) Do not clean the pump with cleaning oil or gasoline when the plug assembly is installed to avoid denaturation of the 0-ring.
(3) Points for attention when replacing gaskets
1) Before installing the gasket, make sure that the seal face is clean, free of burr rust and smooth.
2) The gasket shall not be pulled and twisted, shall not be damaged, and shall not be contaminated with stains, impurities, dust
or dirt.
3) Make sure the gasket is flattened to avoid wrinkling when fastening.
(4) Points for attention when replacing nylon lock nuts
1) Do not clean the pump with cleaning oil or gasoline when the nylon lock nut is installed to avoid denaturation.
2) The nylon lock nuts should be kept clean and should not be contaminated with stains, impurities, dust or dirt.
3. Disassembly procedure for the pump
(1) Before disassembly
 Cut off the motor power.
 Close the valve to prevent the system liquid from flowing out.
(2) Precautions for disassembly
 Before disassembling the pump, thoroughly drain residues out of the pump.
2
1
20
31 19
12b
12a
12b 12a
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25 24
11
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17
12
14
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15
8
17
7
32
10
29
28
1. Water inlet body
2. Plug assembly
4. Impeller
7. Water outlet body
8. Mechanical seal
10. Base
11. Pull rod
12. Guide vane
12a. Port ring cover 12b. Port ring
14. Long spacer sleeve
of impeller
15. Sealing sleeve
17. Sealing gasket
19. Shaft-end sleeve
20. Nylon lock nut 24. Spring washer
25. Hexagonal nut
28. Bolt
29. Spring washer
31. Flat washer
32. Motor
Do not place the water pump vertically during disassembly, so as to avoid residual water
from the pump body entering the motor casing or rotor.
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