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HEATING BOILERS: Astra G-120E
• ELECTRONIC BOILER REGULATOR KR-4.4
The electronic boiler regulator KR-4.4 is designed for controlling a solid fuel boiler. It controls the ventilator in accordance
with the PID regulation law and the circulation pump of the system, by position “on-off”. The regulator adjusts the rotation
speed of the ventilator using the impulse method, thus intensifying or slowing down the burning process. The speed of the
ventilator is defined in proportion to the actual temperature deviation from the set temperature, the duration of the deviation
and the speed of temperature change of the boiler. The regulator reacts to the water temperature in the boiler and smoke
temperature in the flue. A NTC-type sensor for measuring water temperature is installed in the special immersion pocket 18
(Fig. 1), the outer side of which is submerged in water inside the boiler. A PT-type sensor for measuring smoke temperature
is installed in the special sleeve 16 (Fig. 1), which is located in the flue gases duct of the boiler.
The digital temperature indicator 1 (Fig. 11) indicates both the measured and the set temperature of water in the boiler. The
setpoint temperature is adjusted using the buttons 2. After a short press of “+” or “-” the digital indicator 1 starts showing
the setpoint temperature of the boiler water. In order to change it, the appropriate button must be pressed: “+” for increasing
and “-” for decreasing the temperature. After several seconds after the last press of a button, the setpoint temperature is
saved and the indicator returns to showing the measured temperature of the boiler water.
When it indicates the setpoint temperature, a dot lights up beside the readout. When the indicator indicates the real
measured temperature, the dot does not appear. The regulator allows adjustment of the temperature within the range of
65-90°C.
Lamp 3 “Firing on” indicates the active status of the boiler. This lamp lights up when the ventilator is switched on using the
button 3 (Fig. 9) on the front control panel and regulation of the ventilator speed starts. The ventilator can be in operation
mode only when the signal lamp 3 (Fig. 11) lights.
Lamp 4 lights up when the boiler turns to the mode “Firing off”. This boiler operation mode is established if the following
condition occurs:
• if during operation the temperature of flue gases
drops bellow 75°C and does not rise for some time.
Lamp 5 “Pump on” lights up when the regulator
switches on the circulation pump of the system. In
accordance with the manufacturer’s settings, this
occurs when the boiler water temperature exceeds
60°C. The pump is switched off, when the firing in
the boiler nears the end and the temperature of the
flue gases drops below 75°C. Then, pump indicator
lamp 5 switches off as well. Service programming
mode can be used to adjust other limit temperatures
for switching the circulation pump on (in the range
of 55-73°C) and off (in whatever temperature range). To carry out such adjustment, a servicing company should be contacted.
Lamp 6 “Ventilator on” lights up when the boiler ventilator is operating. The more frequently it blinks, the higher the
rotational speed of the ventilator is, since its blinking frequency corresponds to the impulse frequency of the power supply to
the ventilator. If this lamp is lighting constantly, it means that the ventilator is operating at 100% of its capacity.
Lamp 7 signals that the programming output channel is switched on.
Button 8 is multipurpose, and is used for some support functions and service programming.
The boiler regulator is connected to the boiler circuit in accordance with the scheme shown in Fig. 12. The power supply L2,
Fig. 11 Front panel of regulator KR-4.4
1 - digital temperature indicator; 2 - temperature setting buttons; 3 - lamp “Firing
on”, 4 - lamp “Firing off”, 5 - lamp “Pump on”, 6 - lamp “Ventilator on”, 7 - lamp
“Programmable channel on”, 8 - multifunction button.
1
2
7
3
4
5
6
8
