The unit is only to be used in a closed water system. 
Application in an open water circuit can lead to excessive 
corrosion of the water piping.
When water is not moving inside the system in cold 
weather, freezing is very likely and will damage 
the system.
Checking the water circuit
The units are equipped with a water inlet and outlet for connection 
to a water circuit. This circuit must be provided by a licensed technician 
and must comply with local laws and regulations.
Checking the water volume and expansion vessel pre-pressure
The unit is equipped with a 5 L(for 5/7/9 kW unit, the volume is 2L) 
expansion vessel that has a default pre-pressure of 1.5 bar.
To assure proper operation of the unit, the pre-pressure of the expansion 
vessel might need to be adjusted and the minimum and maximum water 
volume must be checked.
1.  Check that the total water volume in the installation, excluding the 
     internal water volume of the unit, is at least 25L(for 5/7/9 kW unit, 
    the minimum volume is 15L) . Refer to 14 Technical specifications 
    to find the total internal water volume of the unit.
Before continuing installation of the unit, check the following:
■  The maximum water pressure = 3 bar.
■  The maximum water temperature is 70°C 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 
    servicing. An automatic air purge is provided inside the unit. Check 
    that this air purge valve is not tightened too much so that automatic 
    release of air in the water circuit remains possible.
 
A
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9.3 Water pipework
All piping lengths and distances have been taken into consideration.
Requirements
Valve
The maximum allowed thermistor cable length is 20m.
 This is the maximum allowable distance between the 
domestic hot water tank and the unit (only for 
installations with a domestic hot water tank).The 
thermistor cable supplied with the domestic hot water 
tank is 10m in length.
In order to optimize efficiency we recommend installing
the 3-way valve and the domestic hot water tank as 
close as possible to the unit
Thermistor 
cable 
length 
minus 2m
NOTE
■ In most applications this minimum water volume will be 
satisfactory.
■ In critical processes or in rooms with a high heat load though, 
extra water might be required.
■ When circulation in each space heating loop is controlled by 
remotely controlled valves, it is important that this minimum 
water volume is kept even if all the valves are closed.
NOTE
■   If  the installation is equipped  with a  domestic hot  water  tank 
(optional),  please  refer  to  the  domestic  hot  water  tank 
Installation & Owner's Manual.
■   If there is no glycol (anti-freeze) in the system there is a power 
supply or pump failure, drain the system (as shown in the figure 
below).
26
Example
1     Outdoor Unit
1.1  Manometer
1.2  Pressure Relief Valve
1.3  Expansion Vessel
1.4  Plate Heat Exchanger
1.5  Backup Heater
1.6  Air Purge Valve
1.7  Flow Switch
1.8 P_i: Circulation Pump Inside Unit
2     Y-shape Filter
3     Stop Valve (Field Supply)
4     User Interface
6     Drain Valve(Field Supply)
7      Fill Valve(Field Supply)
8      Buffer Tank(Field Supply)
9      Balance Tank(Field Supply)
9.1   Air Purge Valve
9.2   Drain Valve
10    Expansion Vessel (Field 
Supply)
11     P_o: Outside Circulation Pump 
(Field Supply)
12     Collector(Field Supply)
18     Bypass Valve(Field Supply)
Fhl 1...N  Floor Heating Loop
M1...N      Motorized Valve (Field 
Supply)
T1…n      Room Thermostat (Field 
Supply)