Safety And Control Devices - Dimplex LBW 300 Installation And Operating Instructions Manual

2.4

2.4 Safety and Control Devices

The HW HP has the following safety features:
High-pressure switch (HP)
The high-pressure switch protects the heat pump against imper-
missibly high operating pressure in the refrigerant circuit. In the
event of a fault, the pressure switch will switch the heat pump off.
The heat pump restarts automatically as soon as the pressure
once again drops in the refrigerant circuit.
Safety temperature limiter for heating element
(STL)
The STL protects the hot water system against impermissible
temperature increases.
The heating element switches off whenever the set switching
value (99 °C) is exceeded.
The heating element cannot be switched on again until the hot
water temperature has decreased to ≤ 90 °C and the reset but-
ton (illustration) on the STL is then pressed (this may only be
done by qualified personnel).
Device fuse
The HW HP is equipped with a separate fuse to ensure internal
device protection. This fine-wire fuse (1.25 A slow-acting) is lo-
cated in a "screw-type device" (can be screwed apart in the mid-
dle) which is located on the side of the internal electrical connec-
tions (in the area next to the X1 terminal strip).
E-4
The HW HP is equipped with the following regulation and control
devices:
Heating element temperature controller (TC)
The heating element temperature controller regulates the hot
water temperature during heating element operation. The maxi-
mum controller temperature is factory set to 65 °C (the controller
and the STL are installed together in a casing). Temperature set-
tings can be changed using a suitable tool (see illustration).
Changes to this setting may be carried out by qualified personnel
only!
In automatic operation (activated via the air temperature sensor,
see the Section "Air temperature sensor") the water is heated by
the heating element until the fixed-setpoint of the heat pump (ap-
prox. 58 °C) has been reached. In contrast to heat pump only op-
eration, a smaller amount of water is heated up to minimise the
operating period of the heating element. In the manually
switched continuous operating mode of the heating element, the
hot water is heated until the set maximum temperature of the
heating element (65 °C factory setting) has been reached. (With
respective additional wiring, the heating element can also be
switched externally - see the Chapter "Electrical Connection")
Heat pump temperature control electronics
Temperature control in the hot water cylinder and compressor
operation control is carried out by an electronic control system.
This system monitors the water temperature with a sensor and
keeps the fixed-setpoint fairly constant.
Air temperature sensor
This electronic sensor measures the HW HP air intake tempera-
ture (directly upstream of the evaporator). As soon as the air tem-
perature sinks below 14 °C, the hot water preparation is auto-
matically switched from heat pump operation to heating element
operation.