Changing The Pre-Pressure Of The Expansion Vessel; To Check The Water Volume: Examples - Daikin EPRA14DAW1 Installer's Reference Manual

7.1.4 Changing the pre-pressure of the expansion vessel

7.1.5 To check the water volume: Examples

EPRA14~18DAV3+W1 + ETVH/X16S18+23DA6V+9W(G)
Daikin Altherma 3 H HT F
4P587502-1A – 2020.01
Minimum required flow rate
25 l/min
See the recommended procedure as described in
4
commissioning" [ 201].
NOTICE
Only a licensed installer may adjust the pre-pressure of the expansion vessel.
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" [
4
77]).
7 Piping installation
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"10.4 Checklist during
a
Installer reference guide
79