Installation of Indoor Unit
Water Volume and Expansion Vessel Pressure
Inside expansion vessel 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 highest posi-
tion of the water circuit, adjustment is not required.
- To adjust pre-pressure, use nitrogen gas by certificated installer.
Maximum total water volume (liter)
Pre-pressure in Expansion vessel (bar)
20
60
100
140
180
220
260
300
340
2.4
2.1
1.7
1.4
1.0
0.7
0.3
Adjusting pre-pressure of expansion vessel is as following :
Step 1.
Refer "Volume-Height" table.
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.)
Other-
wise, 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 pipe
0.3 : 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.
H : difference between indoor unit and the highest water pipe
V : total water volume of installation scene
V < 230 liter V ≥ 230 liter
H < 7m Case B Case A
H ≥ 7m Case A Case C
Volume-Height Table
Installation Manual
37
ENGLISH
Summary of Contents for Therma V AHUW096A2
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