R32
Split Type - Air Source Heat Pump 20220105
63
3. Water Pipework
3.1 Water Circuit Checks
Hydronic box are equipped with a water inlet and outlet for connection to a water circuit. AI-Thermal Split
units should only be connected to closed water circuits. Connection to an open water circuit would lead to
excessive corrosion of the water piping. Only materials complying with all applicable legislation should be used
Before continuing installation of the unit, check the following:
The maximum water pressure 3 bar.
The maximum water temperature 70
℃
according to safety device setting
Always use materials that are compatible with the water used in the system and with the materials used in
the unit.
Ensure that components installed in the field piping can withstand the water pressure and temperature.
Drain taps must be provided at all low points of the system to permit complete drainage of the circuit during
maintenance
。
Air vents must be provided at all high points of the system. The vents should be located at points that are
easily accessible for service. An automatic air purge is provided inside the unit. Check that this air purge valve is
not tightened so that automatic release of air in the water circuit is possible.
3.2 Water volume and sizing expansion vessels
The units are equipped with an expansion vessel of 5L that has a default prepressure of 1.5 bar. To assure
proper operation of the unit, the prepressure of the expansion vessel might need to be adjusted.
Check that the total water volume in the installation, excluding the internal water volume of the unit, is at
least 40L.
Expansion vessel volume must fit the total water system volume
To size the expansion for the heating and cooling circuit.
The expansion vessel volume can follow the figure below:
Notes:
In most applications this minimum water volume will be satisfactory.
