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

2.3

Safety and Control Devices

The HPWH is equipped with the following safety features:
2.3.1 High-pressure pressostat (HP)
The high-pressure pressostat protects the heat pump from excessive operating pressures in the refrigeration
cycle. In the case of a malfunction, the pressostat switches off the heat pump. The heat pump is restarted
automatically as soon as the pressure in the refrigeration cycle has dropped to an acceptable level.
2.3.2 Safety temperature limiter for immersion heater (STL)
The STL protects the hot water installation from excessive
temperature increases.
When the preset switching value (99 °C) is exceeded, the
immersion heater is switched off.
The immersion heater cannot be restarted unless the hot
water temperature has fallen to ≤ 90 °C and the reset
button (Fig. 2) on the STL has subsequently been pressed
(may be performed by qualified personnel only!).
2.3.3 Appliance fuse
For internal protection, the HPWH is provided with a separate fuse. This fine-wire fuse (1.25 A slow fuse) is
housed within a "screw plug device" (can be unscrewed in the middle) on the side where the internal electrical
connections (in the area adjacent to terminal strip X1) are located.
In addition, the HPWH is equipped with the following regulating and control devices:
2.3.4 Temperature controller for immersion heater (TR)
The temperature controller for the immersion heater regulates the water temperature in the immersion heater
mode of heating. The maximum temperature of this controller is factory-set at 65 °C (the controller is installed in a
common housing together with the STL). The temperature setting can be changed by means of a suitable tool
(see Fig. 2). Any change of this setting may only be performed by qualified persons!
In the automatic mode of operation (activation via air temperature sensor, see 2.3.6), the water is heated by the
immersion heater up to the preset fixed heat pump setpoint (approx. 58°C). When the immersion heater is
manually activated to operate in the continuous mode, the domestic water is heated until the preset maximum
temperature of the immersion heater controller is reached. (The immersion heater – with appropriate additional
wiring – may, as an option, also be designed for external activation – see section "Electrical connection").
2.3.5 Electronic heat pump temperature controller
The temperature control inside the hot water storage tank and the control of the compressor operation is effected
by an electronic controller. It senses the water temperature with the aid of a sensor and keeps the preset fixed
setpoint at a nearly constant level.
2.3.6 Air temperature sensor
This electronic sensor senses the air inlet temperature of the HPWH (immediately at the evaporator inlet). If the
air temperature drops below 14°C water heating is automatically switched from the heat pump mode to the
immersion heater mode of operation.
Fig 2: Resetting STL
6
Reset button
Panel
Partition
STL
85°
B3
30°
F2