Daikin HXHD125A7V1B, Installation Manual

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HXHD125A7V1B
VRVIII system indoor unit
4PW62584-1A – 11.2010
Installation manual
17
How to check if the pre-pressure of the system needs to be changed:
■
Step 1: define the needed leaving water temperature in the
system: e.g. 65°C
■
Step 2: define the maximal water volume in the system with the
default pre-pressure of 1 bar
■
If the total water volume of the system is <150 l:
no change of pre-pressure needed.
■
If the total water volume of the system is >150 l:
change of pre-pressure needed.
Setting the pre-pressure of the expansion vessel
When it is required to change the default pre-pressure of the
expansion vessel (1 bar), keep in mind the following guidelines:
■
Use only dry nitrogen to set the expansion vessel pre-pressure.
■
Inappropriate setting of the expansion vessel pre-pressure will
lead to malfunction of the system. Therefore, the pre-pressure
should only be adjusted by a licensed installer.
Charging water
1 Connect the water supply to a fill valve (field supply).
2 Make sure to open the automatic air purge.
3 When a tank is used, a 3-way valve needs to be installed (refer
to the manual of the domestic hot water tank for details).
4 Fill with water until the manometer indicates a pressure of
approximately 2.0 bar.
Remove air in the circuit as much as possible using the air purge
valves.
For final purging of the unit, operation of the pump is needed.
Therefore, the unit needs to be finally installed.
65°C water temperature
A Pre-pressure (bar)
B System water volume (l)
NOTICE
Never change the pre-pressure of the system to a value
lower than 0.3 bar.
In this example (when the needed water temperature is
65°C) the maximal water volume is 215 l.
INFORMATION
To set the pre-pressure, the expansion vessel needs to be
accessed from the front or the right.
2.50
2.00
1.50
1.00
0.50
0.00
20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270
B
A
NOTICE
■
During filling, it might not be possible to remove all air
in the system. Remaining air will be removed through
the automatic air purge valves during first operating
hours of the system. Additional filling with water
afterwards might be required.
Pump only operation in order to purge the air of the
system is possible through field settings. Refer to field
settings
"[E-04] Pump only operation" on page 31 for
further details.
■
The water pressure indicated on the manometer will
vary depending on the water temperature (higher
pressure at higher water temperature).
However, at all times water pressure shall remain
above 1 bar to avoid air entering the circuit.
■
The unit might dispose some excessive water through
the pressure relief valve.
■
Water quality must be according to EU directive 98/83
EC.