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3. Description
3.1 Construction of the boiler
The main part of the boiler is the cast iron section boiler drum made of grey cast iron according to:
ČSN 42 2415 Grey iron 42 2415 with luminated graphite, or
ČSN 42 2420 Grey iron 42 2420 with luminated graphite
Pressure parts of the boiler correspond to the demands on solidity according to:
ČSN 07 0240 Warm-water and law-pressure steam boilers
ČSN 07 0245 Warm-water and law-pressure steam boilers. Warm-water boilers up to 50 kW output.
The boiler drum consists of sections with the help of pressured boiler nipples and is secured with boiler
screws. The sections create burning and ash space, water space and a convective part. Heat water input and
output are situated at the back part of the boiler.
The back section of the boiler has a smoky chimney – pot and a heat water flange in the upper part, and a
returnable water flange with a socket for filling and draining cock. Stoker and ash door and a firebox door
under them are fixed to the front section.
The whole boiler drum is isolated with a stifling, mineral isolation that reduces losses by sharing heat into the
surroundings. The steel jacket is fitted in colour with a quality comaxite paint.
At the boiler three types of medium sections are used: in the front part of the boiler (except the three and four
– section size) there is a section with a recess for easier fuel inserting to the average up to 220 mm, then
sections without a molding, in the back part with a molding. The molding closes the burning space and carries
back the flame and product of consumption from the back space to the front part of the boiler, i.e. by the back
path in smoky draughts it is perfectly taken advantage of the product of consumption heat.
Chart Nr. 3 Medium sections of the boiler
Section number 3 4 5 6 7 8 9 10
Medium section with a recess - - 1 1 1 1 1 1
Medium section with a molding 1 2 2 3 4 5 5 6
Medium section without a molding - - - - - - 1 1
3.2 Regulating and security elements
Smoke flap of the smoke extension regulates the output amount of flue gases from the boiler to the chimney.
It is controlled by a handgrip at the rear of the boiler.
The choker (stifling) of the ashpan door regulates the supply of combustion air under the grate of boiler. It is
controlled manually by means of an adjusting screw of the choker (stifling).
The air rosette of stoking door is used for supply of the secondary air into the combustion chamber. To
control the rosette it is necessary to use a tool because of a higher surface temperature of the stoking door.
The small cover for cleaning of the smoke extension that is located in its bottom part serves for cleaning the
deposits resulting from the combustion.
A combined device - thermo-manometer is used to detect the temperature of heating water and water
pressure in the heating system. This device is placed in the upper part of the jacket. The thermowell of the
sensor of the thermo-manometer is located at the top of the rear boiler section.
