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Installation and operation manual
10
HXY48TAVJU
VRV System indoor unit
3P616151-1A – 2021.12
6.2.5.
Changing the pre-pressure of the expansion vessel
When changing the default pre-pressure of the expansion vessel
(14.5 psi (1 bar)) is required, 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 schräder
valve of the expansion vessel.
a Valve
6.2.6.
To check the water volume: Examples
Example 1
The indoor unit is installed 16 ft (5 m) below the highest point in the
water circuit. The total water volume in the water circuit is 26 gal
(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 92 gal (350 l).
Actions:
Because the total water volume 92 gal (350 l) is more than the
default water volume 74 gal (280 l), the pre-pressure must be
decreased.
The required pre-pressure is:
Pg = (4.35+H/10) = (4.35+0/10) = 4.35 psi (0.3 bar)
The corresponding maximum water volume at 4.35 psi (0.3 bar)
is 108.3 gal (410 l). (See the graph in the chapter above).
Because 92 gal (350 l) is lower than 108.3 gal (410 l), the
expansion vessel is appropriate for the installation.
6.3.
Preparing electrical wiring
6.3.1.
About preparing electrical wiring
NOTE
Only a licensed installer may adjust the pre-pressure of the
expansion vessel.
a
WARNING
Establish proper earthing. Do NOT earth the unit to a
utility pipe, surge absorber, or telephone earth.
Incomplete earthing may cause electrical shock.
Install the required fuses or circuit breakers.
Secure the electrical wiring with cable ties so that the
cables do NOT come in contact with the piping or
sharp edges, particularly on the high-pressure side
Do NOT use taped wires, stranded conductor wires,
extension cords, or connections from a star system.
They can cause overheating, electrical shock or fire.
All wiring must be performed by an authorized
electrician and must comply with the applicable
legislation.
Make electrical connections to the fixed wiring.
All components procured on the site and all electrical
construction must comply with the applicable
legislation.
WARNING
The indoor unit should have a dedicated power
supply.
580
1 50
0
0
a
b
1
a Normal power supply
b Fuse
1 Power supply for indoor unit
01_EN_3P616151-1A.fm 10 ページ 2021年12月14日 火曜日 午後1時29分