125A8V1BF
VRV IV System indoor unit
4P405267-1C – 2021.04
Installation and operation manual
9
6.2.2. Water circuit requirements
Use the indoor unit only in a closed water system.
Using the system in an open water system will lead to excessive
corrosion.
Maximum water temperature is 45°C (heating) and mimimum
water temperature is 5°C (cooling).
The maximum water pressure is 3 bar.
Provide adequate safeguards in the water circuit to ensure that
the maximum pressure is NOT exceeded.
All installed piping and piping accessories (valve,
connections,…) must withstand the following temperatures.
a Outdoor unit (VRV IV heat pump)
b Indoor unit HXY(080/125)
c Heat exchanger
d Pump
e Shut-off valve
f Motorised 2-way valve (field supply)
g Collector
FCU1...3 Fan coil unit (optional)
FHL1...3 Floor heating loop (optional)
T Room thermostat (optional)
Shut-off valves delivered with the unit should be installed so that
normal servicing can be accomplished without draining the
system.
Make all water piping connections in accordance with the
applicable legislation and the outlook diagram that is delivered
with the unit, respecting the water inlet and outlet.
Do NOT use excessive force when connecting the piping.
Deformation of the piping can cause malfunctioning of the unit.
Provide drain taps at all low points of the system in order to allow
complete drainage of the water circuit.
Provide a proper drain for the pressure relief valve to avoid
water coming into contact with electrical parts.
Provide air vents at all high points of the system, which must
also be easily accessible for servicing. An automatic air purge is
provided in the indoor unit. Check that the air purge is NOT
tightened too much, so that automatic release of air in the water
circuit is possible.
Only use materials that are compatible with water used in the
system and with the materials used in the indoor unit.
Check that all components in the field piping can withstand the
water pressure and water temperature.
When using non-brass metallic piping, insulate the brass and
non-brass properly so that they do NOT make contact with each
other. This to prevent galvanic corrosion.
Never use Zn-coated parts in the water circuit. Because the
unit's internal water circuit uses copper piping, excessive
corrosion may occur.
Only use appropriate tooling to handle brass, which is a soft
material. If NOT, pipes will get damaged.
Select the water piping diameter in relation to the required water
flow and the available external static pressure of the pump. See
"14. Technical Data" on page 40
for the external static pressure
curves of the indoor unit.
You can find the minimum required water flow for the indoor unit
operation in the following table. When the water flow is lower,
flow malfunction A6 will be displayed and the indoor unit will be
stopped.
It is strongly recommended to install an additional filter on the
heating water circuit. Especially to remove metallic particles
from the field heating piping, it is advised to use a magnetic or
cyclone filter, which can remove small particles. Small particles
may damage the unit and will NOT be removed by the standard
filter of the heat pump system.
If air or dust gets into the water circuit, problems may occur. To
prevent this:
Only use clean pipes
Hold the pipe end downwards when removing burrs.
Cover the pipe end when inserting it through a wall, to
prevent dust and/or particles entering the pipe.
Use a decent thread sealant to seal connections.
For safety reasons, it is NOT allowed to add any kind of glycol to
the water circuit.
The installation must be in compliance with the applicable
legislation and may require additional hygienic installation
measures.
In accordance with the applicable legislation, it may be
necessary to install thermostatic mixing valves.
6.2.3. Formula to calculate the expansion vessel pre-pressure
The pre-pressure (Pg) of the vessel depends on the installation
height difference (H):
Pg=0.3+(H/10) (bar)
6.2.4. To check the water volume
The indoor unit has an expansion vessel of 10 litre with a factory set
pre-pressure of 1 bar.
To make sure that the unit operates properly:
You must check the minimum and maximum water volume.
You might need to adjust the pre-pressure of the expansion
vessel.
INFORMATION
The following illustration is an example and may NOT
match your system layout.
M
T
FCU2
FCU3
FHL1
FHL2
FHL3
a
b c
d
e
e
f
g
g
g
g
65°C
Model
Minimum water flow (l/min)
HXY080A8V1B
15
HXY125A8V1B
15
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