Midea MGBT-F120W/PN1, Manual

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MCAC-ATSM-2014-09 R410A tropical air-cooled scroll chiller unit 60Hz
85
● For the water pipeline network including filters and heat exchangers, dreg or dirt may seriously damages
the heat exchangers and water pipes.
● The installation persons or the users must ensure the quality of chilled water, and de-icing salt mixtures
and air should be excluded from the water system, since they may oxidize and corrode steel parts inside the
heat exchanger.
12.2.2 Water Quality
※
Water quality control
When industrial water is used as chilled water, little furring may occur; however, well water or river water,
used as chilled water, may cause much sediment, such as furring, sand, and so on. Therefore, well water or
river water must be filtered and softened in softening water equipment before flowing into chilled water
system. If sand and clay settle in the evaporator, circulation of chilled water may be blocked, and thus
leading to freezing accidents; if hardness of chilled water is too high, furring may occur easily, and the
devices may be corroded. Therefore, the quality of chilled water should be analyzed before being used, such
as PH value, conductivity, concentration of chloride ion, concentration of sulfide ion, and so on.
※
Applicable standard of water quality for the unit
PH
value Total
hardness Conductivity Sulfide
ion Chloride
ion Ammonia
ion Sulfate
ion Silicon Iron
content Sodium ion Calcium
ion
7
～
8.5
<50ppm
<20μV/cm(25
℃
) No <50ppm No <50ppm <30ppm <0.3ppm No
requirement <50ppm
Performance adjustment factors
The chilled fluid must be required according to anyone condition as following:
1. The outlet water temperature is below 5
o
C;
2. The ambient temperature is below 0
o
C;
3. Don
’t start up the unit for a long time.
4. The power supply was cut off and needn
’t change the water in system.
Ethylene and Propylene Glycol Factors
A glycol solution is required when the unit with condition as mentioned. The use of glycol will reduce the
performance of the unit depending on concentration.
Ethylene Glycol
Quality of glycol
（
%
）
modification coefficient
Freezing
point
℃
Cooling capacity
modification
Power
modification
Water
resistance
Water flow
modification
0 1.000 1.000
1.000 1.000
0
10 0.984 0.998 1.118 1.019 -4.000
20 0.973 0.995 1.268 1.051 -9.000
30 0.965 0.992 1.482 1.092 -16.000
40 0.960 0.989 1.791 1.145 -23.000
Propylene Glycol
Quality of glycol
（
%
）
Modification coefficient
Freezing
point
℃
Cooling capacity
modification
Power
modification
Water
resistance
Water flow
modification
0
1.000 1.000 1.000 1.000
0
10 0.976 0.996 1.071 1.000 -3.000
20 0.961 0.992 1.189 1.016 -7.000
30 0.948 0.988 1.380 1.034 -13.000
40 0.938 0.984 1.728 1.078 -22.000
Units operating with glycol solutions are not included in the ARI Certification Program.
Altitude correction factors