Daikin Altherma EHBH08DA6V7 - 6.4.5 To check the water volume: Examples

6 | Preparation
Installer reference guide
62
ERGA04~08DAV3(A) + EHBH/X04+08DA*V7
Daikin Altherma 3 R W
4P618958-1 – 2020.03
The default pre-pressure of the expansion vessel is 1 bar. When it is required to
change the pre-pressure, take following guidelines into account:
▪ Only use dry nitrogen to set the expansion vessel pre-pressure.
▪ Inappropriate setting of the expansion vessel pre-pressure will lead to
malfunction of the system.
Changing the pre-pressure of the expansion vessel should be done by releasing or
increasing nitrogen pressure through the Schrader valve of the expansion vessel.
a
1
2
3
a Schrader valve
6.4.5 To check the water volume: Examples
Example 1
The indoor unit is installed 5m below the highest point in the water circuit. The
total water volume in the water circuit is 100l.
No actions or adjustments are required.
Example 2
The indoor unit is installed at the highest point in the water circuit. The total water
volume in the water circuit is 250l.
Actions:
▪ Because the total water volume (250 l) is more than the default water volume
(200l), the pre-pressure must be decreased.
▪ The required pre-pressure is:
Pg = (0.3+(H/10))bar = (0.3+(0/10))bar = 0.3bar
▪ The corresponding maximum water volume at 0.3bar is 290l. (See the graph in
"Maximum water volume"[460]).
▪ Because 250 l is lower than 290 l, the expansion vessel is appropriate for the
installation.