can be changed if necessary). This means that if the start value for hot water production is set to 40°C the heat
pump need not necessarily start hot water production when the hot water sensor displays 40°C but also makes
reference to what temperature the peak water sensor displays. If it is still very hot at the top of the water heater
the start of hot water production will be delayed.
With anti-legionella operation, when the immersion heater heats the water heater to 60°C to prevent growth of
legionella bacteria, the peak water sensor temperature has no impact, only the hot water sensor has control. Anti-
legionella is factory set as top heating interval every 7th day.
4.6
Defrost function
The heat pump defrosts (see figure below).
Note! The designations for condenser and evaporator are switched during the defrost function (like the
cooling function) compared to the heating function, because the designations follow the cooling
technical function that respective units have (evaporation respectively condensing).
When the compressor (1) receives a start signal the refrigerant is compressed in gas form via the 4 way valve (5) to
the air exchanger (15). The hot refrigerant gives off heat to the air exchanger (15), shifts to liquid phase and contin-
ues to the plate heat exchanger (7). In the plate heat exchanger (7) the refrigerant is heated to gas form by the
hotter heating system (6). The heating system is cooled. The refrigerant continues via the 4 way valve (5) back to
the compressor (1).
3
2
1
19
18
17
15
14
16
11
13
12
10
9
8
7
6
5
4
Position Description
Position Description
1
Compressor
11
Electronic expansion valve
2
Operating pressure switch
12
Non-return valve
3
High pressure switch
13
Solenoid
4
Discharge pipe sensor
14
Refrigerant sensor 2
5
Four-way valve
15
Air exchanger (condenser)
6
Heating system (hot return line)
16
Fan
7
Plate heat exchanger (evaporator)
17
Refrigerant sensor 1
8
Heating system ( cold supply line)
18
Pressure transmitter
Installation instructions VMGFD102 – 19
