Hach-Lange Sigma SD900 Portable - Manual (Page 60)

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Maintenance
• Constituents in the sample liquid. Grit and other abrasive solids
cause greater wear on the tube when they are squeezed
through the pump rollers.
6.3.2 Pump tube replacement
Important Note: Use of tubing other than that supplied by the
manufacturer may cause excessive wear on mechanical parts
and/or poor pump performance.
Inspect the pump tubing and rollers on a regular basis. Replace the
tubing when deteriorated, at regular intervals or when the
“change tube” message is displayed (
section 4.9.3 on page 49 ).
Prerequisites:
• Pump tubing—pre-cut or bulk (15 ft or 50 ft)
Note: See Replacement parts on page 69 for ordering information.
Removal procedure:
1. Turn off the controller power.
2. If using bulk pump tubing, cut a 23.25 inch piece and mark the
tube with alignment dots at the locations shown in Figure 21 .
3. Disconnect the old pump tubing from the liquid sensor and from
the tube fitting on the sampler housing.
4. Loosen the thumbscrew on the pump cover and open
the cover.
5. Pull the tube from the pump tube track while turning the rotor to
remove the old tubing from the pump.
6. Clean the silicone residue from the interior of the pump housing
and from the rollers (see section 6.3.3 on page 60 ).
Figure 21 Pump tubing measurement
1 To liquid sensor 3 Inside pump body
2 Alignment dot 4 To tube fitting on center section