48 | LOOP CIRCUIT DESIGN
LOOP CIRCUIT DESIGN | 49
W
ater Loop Circuit Design
Multi V W
ater 5 575V Source Unit Engineering Manual
© LG Electronics Canada, Inc., North York, ON Canada. All rights reserved. “LG” is a registered trademark of LG Corp.
© LG Electronics Canada, Inc., North York, ON Canada. All rights reserved. “LG” is a registered trademark of LG Corp.
Freeze Protection
The piping system must be protected from freezing during winter conditions. Heating mode of the water source unit will reduce water loop
temperature. The addition of antifreeze may lower the performance of the water source unit due to reduced heat transfer and added pressure
drop. LATS system design software has options to add antifreeze and calculate reduced capacity. To manually calculate capacity reduction,
follow these steps:
1. Find the appropriate system cooling or heating correction factor in the following Table.
2. Multiply the cooling or heating correction factor by the water source unit capacity to find the NET water source unit capacity.
3. Apply the appropriate system pressure drop correction factor from the Table below and multiply by the water source unit pressure drop to
find the net water source unit pressure drop.
Antifreeze Type
Item
Antifreeze % by weight
10%
20%
30%
40%
50%
Methanol
Cooling
0.998
0.997
0.995
0.993
0.992
Heating
0.995
0.99
0.985
0.979
0.974
Pressure Drop
1.023
1.067
1.091
1.122
1.160
Ethylenel Glycol
Cooling
0.996
0.991
0.987
0.983
0.979
Heating
0.993
0.985
0.997
0.969
0.961
Pressure Drop
1.024
1.068
1.124
1.188
1.263
Propylene Glycol
Cooling
0.993
0.987
0.98
0.974
0.968
Heating
0.986
0.973
0.96
0.948
0.935
Pressure Drop
1.040
1.098
1.174
1.273
1.405
Table 28: Antifreeze Correction Factors
Water Quality Requirements
Impurities in the water can influence the performance and life expectancy of the water source unit. Use a local water treatment professional to
test and treat the water. Use inhibitors in the water loop, especially if the water temperature is operated above 104°F. Ensure all air is purged
from the system. Maintain the following levels:
Item
Closed Type System
Effect
Circulating Water
Supplemented Water
Corrosion
Scale
Basic Items:
pH [77° F]
7.0 ~ 8.0
7.0 ~ 8.0
O
O
Conductivity [77° F] mS/m
Below 30
Below 30
O
O
Chlorine ions (mg Cl
-
/L)
Below 50
Below 50
O
–
Sulfate ions (mg SO
4
2
2/L)
Below 50
Below 50
O
O
Acid consumption (pH4.8) (mgCaCO
3
/L)
Below 50
Below 50
–
O
Total Hardness (mg CaCO
3
/L)
Below 70
Below 70
–
O
Calcium Hardness (mg CaCO
3
/L)
Below 50
Below 50
–
O
Ionic-static silica (mg SiO
2
/L)
Below 30
Below 30
–
O
Reference Items:
Iron (mg Fe/L)
Below 1.0
Below 0.3
O
O
Copper (mg Cu/L)
Below 1.0
Below 0.1
O
–
Sulfate ion (mg SO
4
2
/L)
Must not be detected Must not be detected
O
–
Ammonium ion (mg NH
4
+
)L
Below 0.3
Below 0.1
O
–
Residual chlorine (mg CL/L)
Below 0.25
Below 0.3
O
–
Free carbon dioxide (mg CO
2
/L)
Below 0.4
Below 4.0
O
–
Stability index
–
–
O
O
Table 29: Water Test Levels
O = possibility of occurrence
WATER DESIGN GUIDE
Figure 14: WSU Water and Refrigerant Connections Diagram
Gate Valve
Pressure
Gauge
Temperature
Gauge
PT Service Port
(For Cleaning
Heat Exchanger)
Gate Valve
Strainer
(50 Mesh)
Refrigerant Pipes
Water Inlet
Pipe
Flow Switch
Water Outlet
Pipe
Water Balancing Valve
Dielectric
Pipe Union
Dielectric
Pipe Union
Pressure
Gauge
Temperature
Gauge
Flex
Connector
Flex
Connector
Note
: Before startup, remove the factory jumper at the flow switch
terminals and install a field supplied flow switch.
WATER DESIGN GUIDE
Piping System, continued
• Dielectric pipe unions to prevent the possibility of galvanic corrosion.
• Pressure gauge at inlet and outlet.
• Thermometers at inlet and outlet.
• Flexible connectors at inlet and outlet.
• Shutoff valves at the inlet and outlet to permit service of the WSU.
• Condensate drain trap per local code.
• Service port with hose connections at inlet and outlet to flush the WSU heat exchanger when isolated from the water loop system.
Other considerations:
• Inhibitors must be used in the water loop, especially if water temperature operates above 104°F.
• Maintain water quality requirements.