15
7.3. BURNING
During normal exploitation of boiler burning process is based on periodic refueling and
raking a grate by moving the arm of mobile grate mechanism (pos. 11* ). Single load of
basic fuel is sufficient for 6 hours of boiler operation at rated power. With lower
capacity the period of slow burning (time gap between refueling) may be elongated to
several hours.
When refueling the controller should be switched off, then slowly open the fuel charge
door, introduce another load of fuel, close the door and switch on the controller again. In
emergency situations (blackout), open ash box door, switch the controller off the mains, in
order to prevent ventilator from working once electric power is resumed. Otherwise
fumes may be blown out into boiler room. In the central heating installation heating
requirement is changing along with outdoor conditions, e.g. daytime and temperature.
Temperature of water leaving out the boiler depends also on thermal characteristic of
building, e.g. construction materials, in particular the insulation one. With boilers of SAS
NWT type, regulation of combustion intensity and heat capacity, depending on weather
conditions, is done by microprocessor controller. The controller ensures optimal combustion
process, by regulating fan and circulation pump work. Fan’s rotational speed depends on
measured temperature and parameters setting. Once fire up process is finished, and boiler
riches required temperature, the controller keeps it constant. If boiler’s temperature is
lower than set, rotation speed of fan is increased, if it is higher, scavenges of the
boiler are only performed.
7.4.CLEANING THE BOILER
In order to use fuel in the safe manner, and to get declared boiler’s power and heat efficiency,
keeping adequate cleanliness of combustion chamber and convection channels is
indispensable.
As far as furnace chamber of the boiler is considered, special attention should be paid when
removing ash and slag from between grate orifices and chamber’s walls. Such a cleaning
should be exercised prior each boiler’s fire up process, but not less than after 150÷260
of boiler’s continuous work. Cleaning of convection channels, with volatile ashes
residues, should be performed every 3÷7 days, depending on quality of burned fuel. The
cleaning operation is done through washout holes indicated on the drawing (p. 13, pos.
15, 17). Once cleaning is finished, those wholes should be sealed tightly.
Cleaning the chimney duct is not less important. In case of low temperatures in boiler in
the longer time, it is necessary to “heat” the boiler periodically (at least once a week)
(burning-out in temperature 70÷80°C). This is important for extending the durability of
boiler.
7.5. END THE HEATINHG SEASON
Once heating season is finished, or in other cases of scheduled stops, wait the fuel to
be completely burned out. Once boiler is out and cooled down, remove from the furnace all
remains of burned fuel and apply cleaning and conservation of the entire boiler. Pay
special attention to lubricate inner partitions and movable elements with oil.
*Does not apply to boilers of power above 36kW
