To Check The Water Volume: Examples; Connecting Water Piping; About Connecting The Water Piping - Daikin Altherma 3 H HT F Installer's Reference Manual

8.1.5 To check the water volume: Examples

8.2 Connecting water piping

8.2.1 About connecting the water piping

EPRA14~18D + ETVH16SU18+23E
Daikin Altherma 3 H HT F
4P644738-1A – 2022.03
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 Schrader valve
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" [
▪ Because 250 l is lower than 290 l, the expansion vessel is appropriate for the
installation.
Before connecting the water piping
Make sure the outdoor and indoor unit are mounted.
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Installer reference guide
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