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WATER DESIGN GUIDE
Design Steps
A Multi V Water 5 575V system requires a water cooling/heating source. This year-round heating and cooling system must have a two-pipe
closed- loop water circuit that circulates water continuously and maintains the temperature of water entering the Multi V Water 5 575V system
between 23°F and 113°F when the Multi V Water 5 575V system is in Cooling mode or Synchronous mode (synchronous mode applies to
heat recovery systems only). In Heating mode, water temperature must be maintained between 14°F and 113°F. See the Multi V Water 5
575V Performance Data Manual for performance at different entering water temperatures.
When entering water temperature is below 59°F, the LG variable water flow control kit Model No. PWFCKN000 is required. At the high end
of this temperature range, a heat rejecter (cooling tower, dry cooler, geothermal well) is required to remove heat, while at the low end of the
temperature range, an auxiliary heat source (boiler, solar panel, geothermal well) must add heat.
Piping, pumps, and accessories must be sized to provide adequate water flow to the water source unit.
Design Schematic
The Water Source Units have factory-installed, stainless-steel plate heat exchangers. To protect these heat exchangers, it is recommended
to use closed cooling towers. If open cooling towers or other open loop systems are used, an intermediate heat exchanger must be added to
protect the water source unit from contaminants and debris in the water system that may foul or clog the heat exchanger. Open loop systems
without an intermediate heat exchanger are not recommended due to risk of freezing, reduction of flow due to scaling or clogging, or other
potential problems caused by improper water quality.
Water Cooling Cycle Diagram
Figure 12: Water Cooling Cycle Diagram
R o o m
1
R o o m
2
R o o m
© LG Electronics Canada, Inc., North York, ON Canada. All rights reserved. "LG" is a registered trademark of LG Corp.
46 | LOOP CIRCUIT DESIGN
C o n t r o l W i r i n g
9 9 ° F
B y p
a s s
T e m p e r a t u r e
V a l v e
Se n s o
r
9 0 ° F
C o n t r o l
W i r i n g
P u m p i n g
3
O p e r a t i o n
Si g n a l
T o O t h e r W a t e r So u r c e
U n i t s
Water Heating Cycle Diagram
Figure 13: Water Heating Cycle Diagram
R o o m
1
R o o m
2
R o o m
3
M e c h
a n i c a
l
R o o m
6 8 ° F
5 9 ° F
Expansion Tank
All closed loop systems must have a bladder type expansion tank installed. The expansion tank will protect the equipment from excess pres-
sures due to expansion of water in the loop.
Heat Source and Storage Tank
There are several sources for heat that can be used for this system. They include the following:
• Electric boiler
• Gas boiler
• Solar heat with storage tanks
• Geothermal fields
• Steam heat from remote central plant
If floor space is available, a heat storage tank can be installed to compensate for the thermal flux of the system. The heat storage tank can
store surplus heat or store heat during the night when electric rates are lower. Closed type storage tanks are recommended to prevent con-
tamination of the water system.
Piping System
The following field supplied components must be installed at each Multi V Water 5 575V Water Source Unit.
• Flow switch at outlet in the horizontal pipe. Wire the flow switch to communication terminals and set to shut off the WSU if flow falls below
50% of WSU design flow. The flow switch must be the normally open type. The flow switch must be installed within at least five (5) pipe
diameters downstream and at least three (3) pipe diameters upstream of elbows, valves, or reducers which can cause turbulence and lead
to flow switch flutter.
• Strainer with minimum 50 mesh screen at inlet. Clean the mesh screen twenty-four (24) hours after startup, and then clean regularly to
prevent water flow blockage.
• A water balancing valve, circuit setter, or flow control valve to regulate proper water flow to each WSU.
© LG Electronics Canada, Inc., North York, ON Canada. All rights reserved. "LG" is a registered trademark of LG Corp.
WATER DESIGN GUIDE
T o O t h e r W a t e r
So u r c e
U n i t s
68°F
5 9 ° F
I n t e r l o c k
O p e r a t i o n
B y p
a s s
T e m p Se n s o
r
V a l v e
C o n t r o l W i r i n g
LOOP CIRCUIT DESIGN | 47
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