IM 676
11
Evaporator Water Flow and Pressure Drop
Evaporator flow rate must fall between the minimum and maximum values shown in the evaporator
pressure drop curve. Flow rates below the minimum values will result in laminar flow which will
reduce efficiency, cause erratic operation of the expansion valve and could cause low temperature
cutouts. Flow rates exceeding the maximum values can cause erosion on the evaporator water
connections and tubes.
Measure the chilled water pressure drop through the evaporator at field installed pressure taps.
It is important not to include the effect of valves or strainers in these readings.
Varying chilled water flow through the evaporator while the compressor(s) are operating is not
recommended.
Figure 6, Evaporator water pressure drop curve
