6
2.
INTENDED USE OF BOILER.
DWS
heating boilers are intended for preheating of water in the
central heating system to the temperature not exceeding 90°C on
the
boiler’s outlet and with operating pressure not exceeding 1.5 bar.
DWS boilers are intended for installation:
•
in the open heating system, in such case boiler should be installed and
protected in the opened system acc. to the standard PN-B-02413:1991.
•
in the closed heating system, if the thermal protection is used (e.g.
thermal safety release valve with automatic filling, series 544) meeting
the requirements of PN-EN-12828 and PN-EN 303-5.
Hint!
DWS boilers are approved for operation as heating sources in a
heating system where the temperature of water does not exceed
90°C.
DWS boilers must be installed and protected in an open system
according to the standard PN-B-02413:1991 - Heating engineering.
Protection of water heating system in an open system.
Requirements.
DWS boilers installed in the closed system should be protected
acc. to PN-EN 12828:2006 - Heating systems in buildings.
Designing of water central heating systems. In case of installation
of a boiler is a closed system it should be protected in accordance
with the standard PN-EN 12828, additionally device intended for
carrying off power excess should be installed in accordance with
the standard PN-EN 303-5 Heating boilers. Part 5: Heating boilers
fired with solid fuels with manual and automatic fuel charging with
rated power of 500 kW
Heating boilers DWS are used in central heating systems and hot
water systems, both gravitational and pump. They are intended for
heating of residential one-family residential buildings and for smaller
public utility facilities. These boilers can also cooperate with hot water
system through a heat exchanger.
Hint!
According to the applicable regulations, that is:
•
the Notice of the Marshal of the Sejm of the Republic of Poland
of 29 June 2018 (Journal of Laws of 2018, item 1351),
•
the Regulation of the Council of Ministers of 7 December 2012
(Journal of Laws, no. 0/2012, item 1468),
•
Regulation of the Minister of Economy, Labour and Social
Policy of July 9, 2003. (Journal of Laws of 2003, no. 135, item
1269), boilers installed in the opened system in accordance with
the recommendations given in the service manual and boilers
with rated power to 70kW installed in the closed system
installations, in accordance with the recommendations given in
the service manual, do not require an operation permit issued by
the given Office of Technical Inspection.
While the boilers with rated power exceeding 70kW installed in
the closed system installation can be used only based on an
operation permit issued by the given Office of Technical
Inspection.
Supervision of boiler is required according to the obligatory regulations
especially in the case when there is no power in the system - the result of
stopping of circulating pumps can be no heat removal what can, in
consequence, can lead to the sudden increase of temperature in the
boiler. Wherefore gravitational by-pass should be made, preferably on the
differential valve which in case of current shortage will automatically
discharge excess of hot water from the boiler.
The boiler combustion chamber is equipped with a removable cast
iron grate and an additional vertical grate protecting against falling out of
the glowing fuel from the furnace after the opening of the doors.
The ash-pan chamber is located below the combustion chamber.
Fuel, which is charged periodically on a cast-iron grate, is combusted and
ash is gravitationally transferred to the ash-pan chamber.
Arrangement of charging, furnace and ash pan doors allows easy
access to cleaning of charging, furnace and ash pan chamber. Cleaning
doors are located on the front wall.
Primary air necessary for a correct run of the combustion process is
gravitationally supplied from the outside through the pivoting lid located in
ash-pan and furnace doors and controlled using a draught controller.
Secondary air is supplied from the front side of the boiler through the
system of ducts and the amount of secondary air is adjusted using a flow
damper installed in the charging doors of the boiler. Additionally, the
secondary is to the ceramic nozzle is led by the flow dampers located on
the sides of the boiler.
Hot flue gas gives up the heat by flowing through the steel heat
exchanger consisting of a system of vertical and horizontal convection
ducts, where they are cooled down when the heat is given up. Swirlers
are located in the horizontal convection ducts to increase the
effectiveness of heat exchange.
Cooled flue gases leave the boiler through a steel flue connected
with a chimney flue.
4.
BOILER EQUIPMENT.
Heating boilers type
DWS
are delivered in the fully assembled state,
with charging and furnace and ash-pan doors as well as with thermal
insulation made of mineral wool, covered with protecting jacket made of
steel sheet.
Table 1. Equipment of the
DWS
boiler.
Standard boiler equipment
Unit
Quantity
Boiler operating manual
pcs.
1
Analogue thermometer
pcs.
1
Horizontal grate
pcs.
1
Pivoting lid*
pcs.
1
Tools for servicing the boiler
set
1
Cast-iron grate
pcs.
1
Draught regulator
pcs.
1
Swirlers
set
1
TMEL VT 1500 heat-resistant packing
pcs.
1
Additional equipment of boiler**
Unit
Quantity
Leveling legs
pcs.
4
Safety fittings
pcs.
1
BVTS thermostatic valve
pcs.
1
A release valve for thermal safety with
automatic filling, series 544
pcs.
1
*installation on your own scope acc. to the assembly manual on pages 37-
38.
**optional equipment, extra paid.
5.
FUEL PARAMETERS.
Hard coal - pea coal, is use as primary fuel used for central heating
boilers type DWS:
3. BOILER DESCRIPTION
DWS boilers are executed in form of a rectangular prism, with
double walls reinforced with staybolts, enclosed from the outside with a
water jacket. The upper part of the furnace chamber is also enclosed with
water jacket. Boiler design is based on a multi-draught structure of flues.
The bottom part of the charging chamber covered with ceramics
made of refractory material, executed in the shape of a nozzle, is a
furnace of the boiler. The nozzle has a system of openings used to supply
additional secondary air to the combustion process intended to increase
the effectiveness of the combustion and flue gas emission. Secondary air
is supplied from the side of the boiler through the system of ducts. A flow
damper intended to adjust the amount of flowing secondary air is installed
in the charging doors.
Correct coal type and assortment ensure:
•
fault-free operation of the boiler,
•
fuel saving in comparison to lower-quality types,
•
reduced emission of harmful chemical substances.
It is not acceptable to use plastics for starting-up fire on the draught
furnace grate! It is forbidden to burn the following items on the grate:
•wet wood,
*chipboards or coated and non-coated board materials,
• calorific value Q
r
:
>28 MJ/kg
• moisture W
r
:
≤7 %
• ash content A
r
:
≤5 %
• volatile matter content V
r
15-25%
• granulation
20-25mm
• sulphur content
< 0.6%
Note!
Supervision of the device in form of every day control of
operating parameters is required on grounds of the specificity of
central heating solid fuel-
fired boiler’s operation. Continuous
supervision of boiler is required in the case when there is no
power.
