The UV lamp inside of the MilliQ unit needs to be replaced about once a year when the message "Exchange UV Lamp" flashes on the display. The manual tells you to call Millipore's technicians for assistance with the replacement. Here's what you need to do.
Put the MilliQ unit on standby.
Pull the MilliQ unit off the wall by sliding it up and then away from the wall. This is a little tricky because the holes in the mounting brackets just barely clear the bolts that anchor the unit to the wall. Be careful -- the unit is fairly heavy. I found it best to stand with one foot in the sink and the other on the top of the rolling steps that we have in lab.
Turn off the MilliQ unit with the rocker switch at the top of the back of the unit.
Disconnect the power cord from the unit.
Take off the cover, the white part with the grainy texture convering the top, right and left sides of the unit:
You will need a special six-cornered star driver. There is one in the Chemistry Student Shop. Borrow the screwdriver bit set in the red plastic case (it can be found on the bench).
Using the star driver, remove the screws from the back of the "feet." (See the RiOs/Elix Binder, figure 1. The MilliQ unit is basically the same. The feet are items O and the screws are items N)
Slide back the feet.
You should be able to work the whole cover almost free now. It is only clipped into place.
In order to remove the cover completely, disconnect the green grounding wire that connects the inner parts of the unit to the cover.
Now you can follow the instructions that come with the UV lamp for the RO system resevoir. There is a copy in the back of the RiOs/Elix Binder. The figures are helpful.
The UV lamp assembly is on the left side of the unit in a stainless steel housing. Make sure that you shut off the unit and disconnected the power cord -- the UV radiation from the lamp can harm your eyes and skin!
Unplug the cord that brings power to the UV lamp.
Unscrew the black aluminum end plug by turning it to the left.
Put on gloves: the ones that come with the replacement lamp or vinyl gloves. That way you will not contaminate the lamp.
Twist and lift the UV lamp to remove it from the stainless steel housing. Put the old lamp in a safe, clean place until you are sure the new lamp is in place and working properly.
Install the new lamp:
Slide the O-ring over the top of the UV lamp until it is about 1 inch away from the top (the end with the pins). (If you're following the resevoir instructions, note that there is no stainless steel washer here.)
Put the lamp into the housing. Position the end plug over the lamp, push down and tighten by turning to the right. Caution: tighten by hand only. Do not overtighten or you will crack the lamp!
Reconnect the power cord to the UV lamp.
Put the cover back on loosely and reconnect the green grounding cable.
Clip the cover back into place.
Slide the feet forward to lock the cover into position.
Replace the screws in the feet with the star driver.
Reconnect the power cord to the MilliQ unit and turn the rocker switch back on. The display will still be flashing "Exchange UV Lamp" because the unit needs to be reset.
Put the unit in standby mode.
Press the Measure Cleaning and Menu buttons at the same time.
Press the menu button four times until you get to the service item "reset UV lamp".
Press Measure and Clean together -- "OK" appears.
Press and hold the Menu button until "standby" appears.
Hang the MilliQ unit back onto the wall.