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HEATING BOILERS: Astra G-120E
The first time, kindle the boiler using only paper and small pieces of wood in order to safely remove the
moisture remaining in the ceramic elements.
Switch on the voltage, using button 2 on the front control panel. The boiler water temperature indicator will light up on the
electronic regulator (Fig. 9). Set the required outflowing boiler water temperature using the temperature setting buttons; we
recommend a temperature of at least 75°C or – even better – a higher temperature. Close the door of the upper combustion
chamber, open the lower door and set the kindling material on fire. Observe the rising water temperature in the regulator
display. Keep the lower door open until the boiler water will heat up to 40°C. Then close the lower door, close the damper 19
of the upper flue by pushing its handle 3 (Fig. 1). Then press shortly the ventilator button 3 into the „START“ position (Fig. 9).
After that, the boiler will operate in automatic mode: it will try to reach and maintain the setpoint temperature of the water
outflowing from the boiler.
When firing the boiler for the first time, the condensation of the residual moisture and drainage of water in the lower
combustion chamber occurs. This is not a shortcoming. After kindling the boiler several times, this phenomenon disappears.
The doors of the boiler combustion chambers should be tightly closed, there should be no flue gases
seeping into the ambience through them. Door tightness is regulated by screwing or unscrewing the hinge
and lock screws of the door.
• FIRE BED AND TIPS FOR EFFECTIVE BOILER STOKING
The hot embers and charcoal in the boiler are called the fire bed. Combustible gases emerge from there and are further
burned in the lower chamber of the boiler. The optimal fire bed height during boiler operation is approximately 4-5 cm above
the bottom of the fuel chamber. The output of the boiler ventilator is deliberately chosen with the purpose of sufficiently
supplying the fire bed with air. Then, the most effective combustion of wood gases takes place. Avoid a situation when the
volume of the fire bed expands several times. This situation can occur if very dry and thinly cut wood gets loaded into the
fuel chamber. Consequently, the volume of the fire bed increases rapidly during the burning process and soon a lack of air
occurs, allowing the combustible gases to escape unburned through the chimney into the atmosphere. An indicator of this
undesirable course is dense fumes emerging from the chimney.
The best way to stoke a boiler is the so-called two stages method. During the first stage, the boiler is stoked with a small
amount of fuel. The aim of this phase is to warm up the boiler and form the optimal fire bed. The second stage is intended for
full fuel loading and to perform the main combustion.
The first stage: Prepare thin-cut wood and paper for an easy start. The volume of loaded fuel should be about 15-20 %
of the fuel chamber’s capacity. Open the upper flue damper 3 (Fig.1) and both boiler doors, put the wood and paper inside.
Kindle the paper, make sure that the firing starts and close the upper door. After the temperature of water in the boiler
reaches 45°C, close the damper and the lower door and turn on the ventilator. Let the boiler burn further for 30 minutes.
The second stage: Load the boiler fully. If wood briquettes are used for stoking, load approx. 70 % of the fuel chamber’s
capacity. Before opening the door, press shortly the ventilator button 3 into the „PAUSE“ position (Fig. 9) The letter “L” will
appear on the display and the ventilator will stop. Open the damper 3 (Fig. 1) by pulling the handle towards yourself, and
after some time, open the upper boiler door very slowly to avoid smoke escaping into the room. Load the fuel, close the door
and push the handle of the damper 3 (Fig. 1). Press shortly the ventilator button 3 into the „START“ position (Fig. 9). The
ventilator will start and the boiler will continue its firing mode.
If you lack time to stoke the boiler in the two stages mode as described above, then stoke it by one stage. The boiler will
operate as usual. But if there is the possibility to do so, use the two stages mode in order to achieve an even more effective
combustion.
