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08 + ERLQ004~008
Daikin Altherma - Low Temperature Split
4P313774-1 – 2012.05
Installer reference guide
24
6 Preparation
Maximum water volume
Use the following graph to determine the maximum water volume for
the calculated pre-pressure.
Example: Maximum water volume and expansion vessel pre-
pressure
6.3.4 Changing the pre-pressure of the expansion
vessel
When changing the default pre-pressure of the expansion vessel
(1 bar) is required, take following guidelines into account:
Q
Only use dry nitrogen to set the expansion vessel pre-pressure.
Q
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 schräder
valve of the expansion vessel.
6.3.5 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 350 l.
Actions:
Q
Because the total water volume (350 l) is more than the default
water volume (280 l), the pre-pressure must be decreased.
Q
The required pre-pressure is:
Pg = (0.3+(H/10)) bar = (0.3+(0/10)) bar=0.3 bar.
Q
The corresponding maximum water volume at 0.3 bar is 410 l.
(See the graph in the chapter above).
Q
Because 350 l is lower than 410 l, the expansion vessel is
appropriate for the installation.
a
Pre-pressure (bar)
b
Maximum water volume (l)
Installation
height
difference
(a)
Water volume
≤
280 l
>280 l
≤
7 m
No pre-pressure
adjustment is required.
Do the following:
Q
Decrease the pre-
pressure.
Q
Check if the water
volume does NOT
exceed the
maximum allowed
water volume.
>7 m
Do the following:
Q
Increase the pre-
pressure.
Q
Check if the water
volume does NOT
exceed the
maximum allowed
water volume.
The expansion vessel of
the indoor unit is too
small for the installation.
(a)
This is the height difference (m) between the highest point of the
water circuit and the indoor unit. If the indoor unit is at the highest
point of the installation, the installation height is 0 m.
0.3
0.5
1
1.5
2
2.5
100
50
0
10
150
200
250
300
350
400
450
a
b
NOTICE
Only a licensed installer may adjust the pre-pressure of the
expansion vessel.
a
Schräder valve
a