Other Procedures

There isn't much else. The only critical thing is the NYUMC chill water supplies to our water chiller. While the water chiller pumps chilled water to R-AXIS, itself needs to be chilled because its compressor will otherwise get burned. This is why the chiller is connected to the NYUMC chill water system, of which the piping configuration is shown in the figure.

Check the house chill water pressure meters frequently. Normal readings from these meters are:

  • Meter A (in-water before regulator): around 160 psi.
  • Meter B (in-water after regulator): between 135 and 145 psi.
  • Meter C (return water): at least 20 psi below that of meter B.

However, very often Meter A would show readings above 180, even 200, psi, which makes the regulator malfuntioned and thus Meter B shows readings almost the same as that of Meter C. When this happens (much more often in the Summer), the chiller will keep turning on-and-off* every few seconds and the return water becomes very hot (you can actually feel it by grabbing the return water pipe). Sometimes this will result in a temperature increase of the circulating water (separate from the house water) to R-AXIS because the chiller's compressor is not working normally. There is not much you can do about it except to call NYUMC house maintenance department IMMEDIATELY and ask them to lower the in-water pressure. If they don't respond, keep calling until they do; otherwise, be prepared for a complete R-AXIS shut down and even flooding in the lab because the pressure may already be too high for the chiller's hoses to take.

You should also change the water filter shown in the drawing as frequently as possible (normally once every couple of months). When you do so, don't forget to close the valves (not shown in the picture) on the pipe. Ask MYUNMC maintenance department for fitlters (two AP110 filters each time).

* When the in- and out-water pressure difference is less than 20 psi, the chiller says "no water to cool me" and always shuts down the compressor whenever it's turned on. On the other hand, the water to chill R-AXIS from the chiller will go up with its temperature. As soon as the temperature is above the preset value, i.g. 60oF, the chiller wakes up the compressor to "drag" down the temperature. These two instructions clash with each other and that's why the chiller keeps turning on-and-off.