Monitoring The Circulation Pump; Frost Protection; Priority Control; Circulation Pump Protection - AEG ETH 13 Bedienung Und Installation

6.3 Monitoring the system pressure
The heating system's integral electronic pressure sensor transmits the information about the water pressure values to the
microprocessor. If the range is exceeded, i.e. for pressures below 0.2 bar and above 2.5 bar, the electric boiler is switched
off and this is indicated via the LEDs on the control unit. The water pressure for cold water should be adjusted in this case so
that the two LEDs light up. The water pressure in this case is approx. 1.5 bar (mid range).

6.4 Monitoring the circulation pump

The function of the circulation pump is checked each time it is switched on. If no water flow is detected for longer than 5 seconds,
the pump is switched off, and a renewed start attempt is carried out after 5 seconds.
After 10 unsuccessful attempts, the pump start of the electric boiler is blocked for approx. 15 minutes. This is indicated by
brief flashing of the LED next to the word "SIEĆ" (MAINS). After 15 minutes, 10 new start attempts are carried out.
Pressing the RESET button cancels the waiting period between the start attempts.
To prevent the circulation pump seizing up, particularly during extended idle periods, the microprocessor starts the circulation
pump for 30 seconds every 24 hours. For this reason, the electric boiler should not be switched off in summer.

6.5 Frost protection

The electric boiler and the heating system are protected against frost. In the event of a fault in the room temperature controller
or connecting cable between the room temperature controller and the electric boiler, the heating system is not protected
against the water freezing.
At a temperature below approx. 7 °C in the appliance, the heating system is switched on and switches off again at approx. 20 °C.
The frost protection can also be switched on manually by turning the temperature selector anti-clockwise as far as it will go,
d
symbol. In this case, the signals of the room temperature controller are ignored.

6.6 Priority control

To avoid overloading the power supply, priority control may be carried out via the electric boiler. Supplying 230 V AC to the
"SP" terminal in the terminal strip takes the instantaneous heating water heater out of operation. The "SP" terminal can also
be used for switching power-OFF periods.

6.7 Circulation pump protection

In the event of a circulation pump fault (e.g. short circuit), the control unit is protected with a 2.5 A fuse. The fuse is on the
right under the front cover of the control unit. The fuse should only be replaced after isolating the voltage.
Sequence when replacing the fuse:
- Isolate the electrical voltage
- Lightly press in the fuse holder with a flat screwdriver and turn anti-clockwise
- Replace faulty fuse, lightly press in the fuse holder and turn clockwise

7. Block diagram

Room
temperature
controller
Microprocessor control
unit
Temperature
sensor
Pressure
sensor
Control unit
Power supply
unit
Temperature
limiter 95 °C
Triac
NTC
temperature
sensor
Circulation pump
Installation - for contractors
Mains
Contactor
Heating
element
19