9.4.1 Check the water circuit
9.4 Water piping
All piping lengths and distances have been taken into consideration.
ValveRequirements
Thermistor cable length minus  2m
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.
If the installation is equipped with a domestic hot water tank (field supply), please refer to the domestic hot water tank 
Installation And 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).
NOTE
 If water is not removed from the system in freezing weather when unit is not used, the frozen water may damage the 
water circle parts.
NOTE
29
The unit is equipped with a water inlet and water outlet for connection to a water circuit. This circuit must be provided by a 
licensed technician and must comply with local laws and regulations.
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.
Example:
5
4
4.2
4.1
10
FHL1 FHL2 FHLn
19
20
Indoor
Outdoor
1
15
16
14
12
14
Modbus
16
7  
15
 
Shut-off valve (Field supply) 
4 
User interface(accessory) 
Filling valve (Field supply) 
4.1 
Balance tank (Field supply) 
Drainage valve (Field supply) 
Automatic bleed valve 
Collector/distributor (Field supply) 
5  
Drainage valve 
10 
P_o: Outside circulation 
pump
 (Field supply) 
Expansion vessel(field supply)   
12  
FHL 
Floor heating loop (Field supply) 
Bypass valve (field supply)
2