16
HEATING BOILERS
: Astra G-18 E, Astra G-25 E, Astra G-32 E, Astra G- 40 E
• rear control Panel
The following safety devices are installed in the rear control panel: thermal fuse
1 and electric fuse 2 (Fig. 10). The purpose of the thermal fuse, otherwise called the
maximum boiler temperature emergency thermostat, is to switch off the boiler
ventilator if water temperature in the boiler exceeds the maximum permissible 95°C
due to unforeseen reasons. The temperature sensor of the thermostat is installed in
a dedicated sleeve 16 (Fig. 1). The burning intensity decreases when the ventilator is
switched off and the water temperature decreases. When the emergency thermostat
trips, the lamp of the ventilator switch 3 on the front panel switches off (Fig. 9) and
the lighting indicator bulb 4 “Firing off” on the electronic regulator lights up (Fig.
11). In this case, it is necessary to find out the causes of tripping and to remove them. After the boiler cools down, the emergency
thermostat can be returned to its normal operating mode. For this purpose, unscrew its cover and depress the red button.
The cause of overheating of the boiler and tripping of the emergency thermostat must be found and
removed. If this is not done, the risk of serious damage to boiler equipment as well as hazard to human health
and life remains. If the user cannot locate and remove the cause of tripping of the emergency thermostat, a
professional servicing company must be consulted!
The electric fuse is designated to protect the elements of the electric circuit in case the current in the mains exceeds 2 A. If the
fuse is damaged, the boiler will not switch on and its indicator lamps will not light. In this case, remove and replace the fuse.
The rear control panel of the boiler is grounded.
• electronic Boiler reGulator kr-4.3D
The electronic boiler regulator KR-4.3D 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
fig. 11 front panel of regulator KR-4.3D
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
1
2
fig. 10 Rear control panel
1. Thermal fuse ; 2. Electric fuse.
