18
HEATING BOILERS
: Astra G-18 E, Astra G-25 E, Astra G-32 E, Astra G- 40 E
• kinDlinG ProceDure of the Boiler
Before kindling the boiler, check whether all requirements indicated in the section 1 are executed.
Open the damper of the upper flue 19 by pulling the handle 3 (Fig. 1) towards yourself. Open the door of the upper
combustion chamber, put dry smaller kindling wood pieces and paper on the ceramic bottom so that the paper protrudes into
the lower combustion chamber through the rectangular opening of the ceramic burner 1 (Fig. 2) – this way, it will be easy
to kindle the boiler through the lower combustion chamber. Put some of the easily flammable materials and larger pieces of
kindling wood and firewood atop. Load the wood without any large gaps at the top of combustion chamber. Bigger pieces of
firewood should be loaded in the middle and smaller prices at the sides, because the walls of the combustion chamber slow
down the combustion of the bigger pieces of wood, due to their lower temperature.
Do not cover the entire opening of the upper flue 19 (fig. 1) with the wood, because it will make kindling
more difficult.
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 switch on the ventilator switch 3 on the control panel (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
