Operating instructions

IMM AGSB-60 25
CAUTION
Do not use automotive grade antifreeze. Industrial grade glycols must be used.
Automotive antifreeze contains inhibitors that will cause plating on the copper
tubes within the chiller evaporator. The type and handling of glycol used must be
consistent with local codes.
Water Flow and Pressure Drop
The chilled water flow through the evaporator should be adjusted to meet specified conditions.
The flow rates must fall between the minimum and maximum values shown in table on the
following page. Flow rates below the minimum values shown will result in laminar flow that
will reduce efficiency, cause erratic operation of the electronic expansion valve and could
cause low temperature cutouts. On the other hand flow rates exceeding the maximum values
shown 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 valve or strainer pressure drop in these readings.
Table 15, Ethylene Glycol Factors
Freeze
Point
%
E.G
o
F
o
C
Cap. Power Flow PD
10 26 -3.3 0.994 0.998 1.036 1.104
20 18 -7.8 0.979 0.990 1.060 1.256
30 7 -13.9 0.964 0.983 1.092 1.424
40 -7 -21.7 0.943 0.973 1.132 1.664
50 -28 -33.3 0.920 0.963 1.182 1.944
Table 16, Propylene Glycol Factors
Freeze
Point
%
P.G
o
F
o
C
Cap. Power Flow PD
10 26 -3.3 0.985 0.993 1.017 1.120
20 19 -7.2 0.964 0.983 1.032 1.272
30 9 -12.8 0.932 0.969 1.056 1.496
40 -5 -20.6 0.889 0.948 1.092 1.792
50 -27 -32.8 0.846 0.929 1.139 2.128