DHW 300D - DHW 300D+
2.3 Safety and control devices
The domestic hot water heat pump is equipped with the following
safety devices:
High pressure switch (HP)
The high pressure switch protects the heat pump against unac-
ceptably high operating pressure in the refrigerant circuit and
switches the heat pump off in the event of a fault. The heat pump
restarts with a time delay when the pressure in the refrigerant cir-
cuit has dropped again.
Safety temperature limiter for electric heater (STL)
The STL prevents impermissibly high temperatures from devel-
oping in the domestic hot water cylinder.
The electric heater switches off if the set switching value (99 °C)
is exceeded.
The electric heater cannot be switched on again until the domes-
tic hot water temperature has decreased to 90 °C and the reset
button (see illustration) on the STL (under flange cover) is
pressed (this must only be done by qualified personnel).
The domestic hot water heat pump is also equipped with the fol-
lowing regulation and control devices:
Heat pump temperature controller
Temperature control in the domestic hot water cylinder and the
regulation for compressor operation is carried out by the control
electronics. Electronic sensors measure the water temperature,
which is regulated based on the setpoint. The desired tempera-
ture level (setpoint) is set via the keypad on the control panel.
Air intake temperature
The sensor connected to the controller measures the tempera-
ture in the domestic hot water heat pump directly in front of the
evaporator (air intake temperature). If the set switching value is
not reached (-7 ±1 °C, reset value 2 K,
delay 30 min), the domestic hot water preparation is switched au-
tomatically from heat pump operation to heating element opera-
tion.
EN-4
2.4 Temperature sensor
2.4.1 Temperature sensor
installation position
R1
Air inlet sensor
R3
Domestic hot water sensor
R5
Domestic hot water renewable sensor (optional)
R12 Defrost end sensor
R13 Renewable sensor (optional)
2.4.2 Measured values temperature
sensor
Measured values NTC 10 sensor (R1, R3, R5, R12)
Temperature in °C
NTC-10 in k
15
20
14.9
12.1
Measured values PT 1000 sensor (R13)
Temperature
in °C
PT 1000 in k
60
70
1.23
1.27
2
1
451905.66.02 · FD 9511
-20
-15
-10
-5
67.7
53.4
42.3
33.9
25
30
35
40
45
10.0
8.4
7.0
5.9
5.0
-30 -20 -10
0
10
0.88
0.02
0.96
1.03
1.00
2
2
1
9
80
90 100 110 120 130 140 150 160
1.30
1.34
1.38
1.42
1.46
1.49
9
7
5
3
1
8
0
5
10
27.3
22.1
18.0
50
55
60
4.2
3.6
3.1
20
30
40
50
1.07
1.11
1.15
1.19
8
7
5
4
1.53
1.57
1.61
6
3
1
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