Water Volume And Expansion Vessel Pressure - LG Therma V AHUW056A3 Engineering Product Data Book

THERMA V
Split Type
7. Hydraulic Performance

7.2 Water Volume and Expansion Vessel Pressure

Expansion vessel inside Hydro Box Unit is included which is 8 liter capacity with 1 bar pre-pressure. That means,
according to the volume-pressure graph, total water volume of 230 liter is supported as default. If total water volume
is changed because of installation condition, the pre-pressure should be adjusted to secure proper operation.
• Minimum total water volume is 20 liter.
• Pre-pressure is adjusted by the total water volume. If the indoor unit is located at the highestposition of the water
circuit, adjustment is not required.
• To adjust pre-pressure, use nitrogen gas by certificated installer.
Adjusting pre-pressure of expansion vessel
• Step 1. Refer "Volume-Height" table.
H 7m
H 7m
H : difference between indoor unit and the highest water pipe
V : total water volume of installation scene
If installation scene is belong to Case A, go to Step 2.
Otherwise, if it is Case B, do nothing. (pre-pressure adjustment is not required.)
Otherwise, if it is Case C, go to Step 3.
• Step 2. Adjust pre-pressure by following equation.
Pre-pressure [bar] = (0.1xH+0.3) [bar]where H : difference between indoor unit and the highest water pipe0.3
: minimum water pressure to secure product operation
• Step 3. Volume of expansion vessel is less than installation scene.
Please install additional expansion vessel at the external water circuit.
2.4
2.1
1.7
1.4
1.0
0.7
0.3
20 60 100 140
Maximum total water volume (liter)
V
Case B
Case A
180 220 260
230
Hydro Box Unit
300 340 360
V 230
Case A
Case C
13