Bio-Rad BioLogic LP System - Manual (Page 95)

6.4 CARE OF THE PROPORTIONING VALVE AND MIXER
Normally, the only maintenance required is to flush the Proportioning Valve with water. To do this, use the
Pump’s manual mode to set the buffer to 50%B. Place both inlet tubes in a vessel of water and pump until
the salt is purged from the valve. Do not leave high salt buffers in the valve, as the crystallized salt may
damage the valve. To more vigorously clean the mixing chamber of residue such as salt:
1. Disconnect the Mixer’s cable from the BioLogic LP Controller.
2. Use a 3/8” socket driver or box wrench to carefully remove the top of the mixer by rotating the top coun-
terclockwise.
3. The magnetic stir bar may be removed from the mixing chamber by turning the unit upside down and
tapping the unit in the palm of your hand until the stir bar drops out of the chamber.
4. The mixing chamber and top may now be cleaned as required.
5. The chamber can be flushed by connecting a luer-tipped syringe to the “A” port and slowly passing fluid
through the valve and mixing chamber. Do not attempt to force liquid through the closed “B” port; this
may damage the proportioning valve.
To reassemble the unit:
1. Wipe the mixing chamber and threads clean.
2. Insert the stir bar back into the mixing chamber with the flat end of the stir bar toward the bottom of the
chamber. Gently push the stir bar to the bottom of the chamber.
3. Wipe the top and threads clean.
4. If the 1.0cm O-ring seal on the top is damaged it must be replaced or the mixer will leak. (Bio-Rad part
number for O-ring: 910-0075.)
5. Use a 3/8” socket driver or box wrench to screw the top on the mixer by rotating the top clockwise until
the lip around the top is just flush with the top of the mixing chamber. The seal is made by a properly
seated O-ring, not by the screw threads. To avoid damaging the unit, do not overtighten the top.
6.5 REPLACING THE LAMP IN THE UV OPTICS MODULE
Indications that a lamp replacement is necessary include an unstable baseline and a decreased response to
a standard concentration of a test chromophore. In this latter case, it is advisable to ensure that the flow cell
is clean and that the correct wavelength filter is chosen before replacing the lamp.
Note: Before performing the following procedure, make sure the BioLogic LP Controller is turned off. This
will eliminate the risk of electric shock to you or damage to the Optics module.
To remove the lamp from the UV Optics Module,
1. Turn off all electrical power to the BioLogic LP Controller and unplug the UV Lamp cable. Wait 10 min-
utes for the UV Optics Module to cool.
2. Remove the filter tray and flow cell, as discussed in the previous section.
88
Maintenance and Troubleshooting