Along the west wall north of the FPD racks is a water chiller for the MAPMTs. This should be checked daily via the "west" camera on Alexi's system. The display is usually opened on the conventional systems computer near the control room exit to the DAQ room. If the camera is not looking at our chiller it can be found by rotating to the north and down about as far as it will go. You should see a few buttons and two lights. There is a sign pointing at a yellow light that indicates the water is low. This light should not be lit. If it is, then water needs to be added at the next opportunity. (Typically a fill of water should last about 2 weeks. If the tank was topped off recently this could indicate a leak.)
On each access the water should be checked at the chiller. This takes about 5 minutes. At the chill Hit the stop button and then remove the black cover and unscrew the plastic cap. There is usually a lot of bubbling that causes a slight overflow. Let that settle and then restart the system, let it run a half minute and stop it again. I have found that stopping and restarting is required to get an accurate measure of the water level. After the bubbles settle use the ruler to measure the depth below the top. Record this in the logbook stored on top of the chiller. Note whether water loss rate has changed much. (A full tank has been lasting without the yellow light coming of for about 2 weeks.) The yellow light comes on when it gets down about 2". Fill as needed but as long as you went this far why not top it off. You can fill to within about 1/2"-1/4" of the top. Fill the plastic Coke bottle from the card board boxes of distilled water so that you can estimate how much you add and note that in the logbook as well. Put back the plastic cap (careful not to cross thread or get too tight). Then press start. (Note you can remove the cap while running without any trouble.)