Position Description
Position Description
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
9
Receiver
19
Temperature transmitter
10
Drying filter
Cooling function is started by the heat pump control unit and is primarily temperature controlled. If the hot water
heater is installed the control unit will alternate between cooling and hot water production with prioritisation for
the hot water requirement.
4.8
Check and safety functions
The heat pump has a number of check and safety functions to protect the installation against damage during
abnormal operating conditions.
The diagram below shows the heat pump's circuits with respective safety functions.
1
3
6
5
7
8
4
9
2
10
Symbol explanation
1
Heat transfer fluid circuit
2
Flow sensor
3
Safety valve, heat transfer fluid circuit, externally mounted
4
Refrigerant circuit
5
Operating pressure switch
6
High pressure switch
7
Pressure transmitter
8
Compressor
9
Fan
10
Discharge pipe sensor
Heat transfer fluid circuit (1)
If the flow in the heat transfer fluid circuit is below the permitted value at heat pump start and before the defrost-
ing blocks the flow sensor (2) heat pump's normal operation, an alarm indicator on the control unit control panel
flashes and a warning text appears in the display of the control panel. The alarm resets itself when the flow
returns.
If the pressure in this circuit exceeds the opening pressure for the safety valve (3), the valve opens, releases the
overpressure and closes again. The safety valve overflow pipe must have an open connection to the drain and
visibly flow into this in a frost-free environment.
Refrigerant circuit (4)
The refrigerant circuit's high pressure side is equipped with a high pressure switch (6) and an operating pressure
switch (5).The operating pressure switch stops the compressor when the operating pressure is reached.
If the operating pressure switch does not work and the pressure continues to increase in the circuit, the high pres-
sure switch activates when its break pressure is reached, whereupon the compressor stops and the heat pump's
normal operation is blocked.
If the high pressure switch is activated an alarm indicator flashes on the control unit's control panel and a warning
text appears in the display of the control panel. The blocked heat pump is reset by setting the operating mode to
OFF and then back to the previously selected mode.
Installation instructions VMGFD102 – 21
