Hach Ultra MET ONE 237AB, User Manual, Page: 33 / 57

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Troubleshooting Procedures
7.3 Pump troubleshooting
If the vacuum pump does not operate, or exhibits any questionable symptoms such as
unusual sound or vibration, it may be removed for maintenance to restore it to optimum
operation.
7.3.1 Disassembly and cleaning of the pump
Prerequisites:
• 1.27 mm or 1.5 mm Allen wrench
To disassemble and clean the pump:
1. Open the counter as described in section 6.2 on page 25 , step 1 to step 3.
2. Remove the pump from the chassis clip.
3. Remove the pump electrical connection.
4. Disconnect the tubing from the pump.
Note: Make sure to note the attachments to the Vacuum (V) fitting and the Pressure (P) fitting.
5. Use a 1.27 mm or 1.5 mm hex key (Allen) wrench to loosen the set screw on the
bracket on top of the pump (refer to
Figure 12 ).
6. Push the bracket to one side and remove it from the pump (refer to Figure 13 on
page 31 ).
7. Remove the top of the pump. Note the locator pin (refer to Figure 14 on page 31 ).
8. Remove pump body (refer to Figure 15 on page 31 ).
9. Remove the carbon vanes and make sure the rotor turns freely (refer to Figure 16 on
page 32 ).
10. Perform steps 1 to 9 in the reverse order to assemble the pump.
Figure 12 Loosening of the set screw
1 Hex Allen key wrench