ATTACK AWP 25 Instructions For Use Manual
W W W . A T T A C K . S K
Combined boiler
ATTACK Wood&PelleT
for Wood And PelleTs
insTrUCTions for Use
2
CONTENTS
CONTENTS ...................................................................................................................................................................... 2
1. GENERAL INFORMATION ....................................................................................................................................... 4
1.1 INTRODUCTION ................................................................................................................................................. 4
1.2. SAFETY ................................................................................................................................................................. 4
1.3 BOILER OPERATION .......................................................................................................................................... 4
1.4 SAFETY ITEMS FOR WORK WITH THE BOILER ........................................................................................... 5
1.5 BOILER MODIFICATION ................................................................................................................................... 5
1.6. BASIC DESCRIPTION OF THE BOILER: ......................................................................................................... 5
1.7 FUEL ....................................................................................................................................................................... 6
1.7.1 WOOD ........................................................................................................................................................... 6
1.7.2 PELLETS ......................................................................................................................................................... 7
1.7.3 ALTERNATIVE FUELS ................................................................................................................................. 7
2. BOILER ASSEMBLY AND INSTALLATION ........................................................................................................... 8
2.1 HANDLING THE BOILER ................................................................................................................................... 8
2.2 GENERAL CONDITIONS OF INSTALLATION ............................................................................................... 8
BINDING NORMS FOR PROJECTING AND INSTALLATION OF THE BOILERS ..................................... 9
2.3 PLACING THE BOILER .................................................................................................................................... 10
2.4 BOILER CONNECTION TO THE HEATING SYSTEM ................................................................................ 11
2.4.1 PROTECTION AGAINST CORROSION ................................................................................................ 12
2.4.2 CHIMNEY ................................................................................................................................................... 13
2.4.3 FLUE GAS CONNECTION OF THE BOILER ........................................................................................ 13
2.4.4 CONNECTION TO THE ELECTRICITY MAINS ................................................................................... 13
2.4.5 CONNECTION OF THE EXTERNAL PELLET TANK........................................................................... 14
2.4.6 LEFT DOOR VERSION ............................................................................................................................. 14
2.4.7 CHOICE AND WAY OF CONNECTION OF THE CONTROL AND SAFETY ELEMENTS ........... 14
2.4.8 CONNECTION TO THE ACCUMULATION TANKS .......................................................................... 16
2.4.9 RECOMMENDED HYDRAULIC SCHEMES OF BOILER CONNECTION....................................... 18
3. BOILER START-UP .................................................................................................................................................. 19
4. WARRANTY CONDITIONS ................................................................................................................................... 19
5. TECHNICAL PARAMETERS .................................................................................................................................. 20
5.1 DIMENSIONS OF THE BOILER ATTACK WOOD&PELLET 25 ............................................................... 21
6. REGULATION OF THE BOILER AND THE HEATING SYSTEM ..................................................................... 22
6.1 IN GENERAL ...................................................................................................................................................... 22
6.2 EMERGENCY ACTIONS .................................................................................................................................. 22
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6.3 PREPARATION FOR THE OPERATION, FILLING THE INTEGRATED PELLET TANK ....................... 23
6.4 DESCRIPTION OF THE SAFETY DEVICES .................................................................................................. 23
6.5 BOILER CONTROL AND OPERATION ........................................................................................................ 24
6.5.1 DESCRIPTION OF THE MAIN CONTROL MODES ........................................................................... 25
6.5.2 DESCRIPTION OF THE CONTROL MODES, RELATION BETWEEN THE MODE WOOD AND
COMBI ................................................................................................................................................................... 26
6.5.3 OPERATION WITH WOOD .................................................................................................................... 26
6.5.3.1 MANUAL LIGHT UP OF WOOD........................................................................................................ 27
6.5.3.2 AUTOMATIC LIGHT-UP OF WOOD................................................................................................. 31
6.5.4 COMBINED OPERATION MODE .......................................................................................................... 33
7. DISPLAYING INFORMATION .............................................................................................................................. 35
8. SETTING THE PARAMETERS ............................................................................................................................... 37
8.1 LEVEL OF SETTING THE BASIC PARAMETERS ........................................................................................ 37
8.2 LEVEL OF SETTING THE ADVANCED PARAMETERS ............................................................................. 39
9. SPECIAL SETTINGS AND INFORMATION ........................................................................................................ 48
10. INTERNET CONNECTION .................................................................................................................................. 49
11. SOFTWARE UPDATES ........................................................................................................................................ 50
12. FACTORY SETTINGS AND RESET .................................................................................................................... 51
13. BOILER MAINTENANCE ..................................................................................................................................... 51
14. BOILER CLEANING .............................................................................................................................................. 52
15. ASSEMBLY AND DISSASSEMBLY OF THE REFRACTORY ITEMS ............................................................ 53
16. TABLE OF RELATION OF THE RESISTANCE AND THE TEMPERATURE OF THE SENSOR PT 1000 54
17. ELECTRICAL CONNECTION SCHEME ............................................................................................................ 55
18. ACCESSORIES ....................................................................................................................................................... 58
19. INSTRUCTIONS FOR DISPOSAL OF THE APPLIANCE AFTER ITS LIFETIME ENDS ............................ 58
19.1 DISPOSAL OF PACKAGING ........................................................................................................................ 58
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1. GENERAL INFORMATION
1.1 INTRODUCTION
Dear customer,
thank you for your trust and purchase of our product – the combined boiler ATTACK WOOD&PELLET.
The boiler construction is based on the newest knowledge of the biomass combustion and meets all
current test criteria and EU directives.
Please read this manual carefully and keep it near the boiler for reference. This manual contains
important information, including information for correct, safe and economical boiler operation.
Constant improvement of our products may mean small differences in the pictures and content and
we reserve right to make technical changes of products without previous announcement.
1.2. SAFETY
The following three warning signs are used in this manual for illustration of the threat of danger
and for important safety notifications:
DANGERNGER
There is imminent danger and serious threat to health or property. Follow the given
instructions!
WARNING
Potentionally dangerous situation that could cause serious threat to health or property if
advised actions are not taken. Take care!
CAUTION
Take care and follow the advised actions.
1.3 BOILER OPERATION
CAUTION
No unauthorized personel to enter the boiler room, there may be serious risk to health or
property. Operator of the system must ensure that no unauthorized person, particularly children,
enter the boiler room.
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1.4 SAFETY ITEMS FOR WORK WITH THE BOILER
To work on the boiler please use correct personal protective equipment including heat resistant
gloves, suitable cloths and safety shoes.
1.5 BOILER MODIFICATION
CAUTION
It is forbidden to make any changes to the construction of the boiler or disable any safety
and protection devices fitted to the boiler.
1.6. BASIC DESCRIPTION OF THE BOILER
The ATTACK WOOD&PELLET is a modern environmentally friendly boiler that saves environment
by efficient burning of biomass. The user gets the advantage of low operating costs from wood
combustion as well as the convenience of the heating system comparable with gas boilers when
burning the pellets. The boiler is intended for heating of dwelling houses, cottages, factories,
industrial units, etc.
Pic. 1 Basic description of the boiler
1 –wood feeding chamber door, 2 –middle door for ignition and cleaning, 3 –combustion
chamber door with a sight-hole, 4 – main door, 5 – burner for pellet combustion, 6 – secondary
and primary air inlet for gasification, 7 – boiler flow connection, 8 – boiler control electronics.
6
The boiler consists of the wood feeding and combustion chamber, pellet combustion chamber,
pellet burner, integrated pellet tank and heat exchanger. The boiler can be operated in either
wood mode or pellet mode, but not at the same time. The boiler is designed with reference to
the user comfort, i.e. to save time for heat-up, fuel cutting, cleaning and total time spent by the
boiler. The basic part of the boiler is a water cooled body, welded from boiler steel plate of 3–
6 mm to ensure long life time. The feeding chamber for gasification is equipped with a dry coat.
By elimination and moving the condensation point from the boiler body to the surface of the dry
coat is the boiler´s life extended. The dry coat can be easily exchanged, if it comes to its damage.
Turbulators in the tubular exchanger improve heat transfer into the heating water and ensure
automatic exchanger cleaning to maintain high efficiency during the operation and to extend
the boiler life. The boiler body is insulated with mineral wool. The covering is powder coated.
1.7 FUEL
1.7.1 WOOD
In the boiler ATTACK WOOD&PELLET it is possible to burn soft and hard chopped fuel wood with
the heat value 15–17 MJ/kg. Particularly suitable is beech, oak, fir, spruce, pine, poplar, alder,
willow, birch, ash, wych-hazel, locust, always within the humidity range of 12–20 %.
Recommended diameter of the wood logs is in the range of 80–150 mm. The maximum length
of wood logs is 580 mm and it must not be exceeded, otherwise they would get stuck in the
feeding chamber.
The heat value of the particular wood types:
Units
Wood Kcal/kg
MJ/kg
kWh/kg
Spruce 3 900 16,25 4,5
Pine 3 800 15,80 4,4
Birch 3 750 15,50 4,3
Oak 3 600 15,10 4,2
Beech 3 450 14,40 4,0
CAUTION
Wrong humidity or size of the wood may cause increase or decrease of output, low or high flue
gas temperature, excessive condensation, flame loss during the gasification process or
uncontrollable combustion.
Recommended storing and drying the wood:
Hard wood: 2 years in dry environment
Soft wood: 1 year in dry environment
When storing (drying) the wood, it has to be protected against rain. To dry the wood more
efficiently, stack to keep as large air gaps as possible. The wood will season faster with airflow
over the wood. If possible, store the wood for at least 1 day at a warm place (e.g. boiler room)
before loading it into the boiler (as it is warm, the efficiency of burning is increased).
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1.7.2 PELLETS
The pressed wood pellets wihout any additional materials can be burned in the boiler.
Parameters of the pellets should be following:
Approved pellet specification:
Measured weight: 600–750 kg/m3
Heat value: 4,7–5,0 kWh/kg
Size/diameter: 6 mm
Size/length: Caution! Max. 35 mm
Humidity – max.: 12 %
Ash content: 0,5–1 %
Content of crumble (dust:) max. 3 %
Ash melting temperature: min. 1 100°C
Norms : DIN 51 731 – HP 5, DIN Plus, or EN 14961-2 – A1
1.7.3 ALTERNATIVE FUELS
It is possible to use the wood briquettes made from pressed wood sawdust without any
additional adhesives or bidning materials.The briquettes must be always mixed in
the appropriate ratio to the wood (dependent on the size and shape of the briquettes) and must
not stuck in the refractory nozzle for wood gasification.
CAUTION
Use of unsuitable fuel types causes higher cleaning requirements and accumulation of an
agressive sediments and condensation that may lead to reduced functionality, damage to the
boiler and invalidate the warranty. Burning the wrong fuels may cause incorrect and
uncontrollable combustion.
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2. BOILER ASSEMBLY AND INSTALLATION
2.1 HANDLING THE BOILER
The boiler is delivered on a pallet. Handle it always on the pallet and put it down from the pallet
only at the point of installation. This can be done by a manipulation trolley or a crane and lifting
eye that is not included into the delivery (recommended specification: lifting screw with an eye
M20 ISO 3266, or M20 DIN 580). The lifting eye can be screwed into the chassis welded on the
upper cover of the boiler to hang the boiler. Carrying capacity of the hanging eye M20 is 1 200
kg, weight of the boiler is approximately 860 kg. Remove the upper boiler cover before hanging
the boiler on the hanging eye.
Pic. 2 Handling the boiler with the hanging screw with eye
2.2 GENERAL CONDITIONS OF INSTALLATION
The boiler can only be installed by a properly certified installer with valid certification to install
and assemble the heating appliances. Before installation, there must be a project made
following to the valid prescriptions. Before installation of the boiler, the worker must check
accordance of the data on the data plate with the data given in the project and documentation
of the boiler. Connection of the boiler must be done in conformity to the valid directives, norms,
ordinances and this instruction manual.
CAUTION
The producer takes no responsibility for damage caused by incorrect connection or
incorrect operation.
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BINDING NORMS FOR PROJECTING AND INSTALLATION OF THE BOILERS
Installation of the boiler must be done in conformity with the following norms:
STN EN 303-5 Heating boilers for solid fuels
STN 92 0300 Fire safety of the local appliances and heat sources
STN EN 60 335.1 +A11 Safety of the electrical appliances for household
STN 06 10 00 Local appliances for solid, liquid and gaseous fuels
STN 06 03 10 Central heating, projecting and installation
STN 06 08 30 Safety devices for central heating and D.H.W. preparation
STN 07 74 01 Water and steam for thermal energetic devices with
operation pressure of steam up to 8 MPa
STN 332000 4-46 Electrical installations of buildings – part 4: Ensuring safety
STN 332000–3 Electrical installations of buildings – part 3: Definition of the
basic characteristics
STN EN ISO 11202 Acoustics. Noise generated by machines and devices.
Definition of the emissions levels of the acoustic pressure at
a workplace and other precisely defined places by using the
approximative corrections in environment. (ISO 11202: 2010)
STN EN ISO 12100 Safety of machines. General principles of construction of
machines. Consideration and elimination of the risk (ISO
12100: 2010)
STN EN 953+A1 Safety of machines. Protection covers. General requirements
for design and construction of fixed and movable covers.
STN ISO 27574-2 Acoustics. Statistical methods for definition and verification
of the determined values of the noise emission of machines
and devices. Part 4: Methods for series of machines.
STN ISO 1819 Devices for fluent cargo transport. Safety prescriptions.
General clauses.
STN EN ISO 15614-1 Requirements for quality of the fusion welding of metal
materials
STN EN 287-1 Welding of reserved technical devices
STN 07 0240 Low pressure boilers, technical prescriptions
STN 07 0245 Warm water boiler with the output up to 50 kW. Technical
requirements, testing
STN 07 7401 Water and steam for heat energy devices with the steam
operating overpressure up to 8 MPa.
STN 73 4210 Manufacturing the chimneys and flue ways and connection
of devices
STN 92 0300:1997 Minimum distance of the external surface of the appliance or
flue way from the building constructions
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2.3 PLACING THE BOILER
The boiler is intended for installation and operation in an area conforming to (AA5/AB5) under
the STN 33 2000-3.
The boiler room must fulfill the above mentioned and the following requirements:
There can be no potentionally explosive environment in the boiler room, as the boiler is not
suitable for usage in such environments.
The temperature in the boiler room must not drop below freezing
Boiler itself does not provide any lighting. The user must ensure sufficient source of light,
according to the local norms and directives.
If the boiler is going to be installed above an altitude of 1 800 m, the installation has to be
consulted with the manufacturer
There must be an opening of at least 200 cm
2
in the boiler room for sufficient ventilation and
supply of the required amount of the air for combustion. The external environment should
not influence the functionality of the opening (rain, snow, wind).
When installing the boiler, it is necessary to keep a safe distance of its surface from
flammable materials, according to the degree of flammability:
from materials of flammability B, C1 a C2 200 mm
from materials of flammability C3 400 mm
from materials with the grade of flammability not approved under the STN 73 0853
400 mm
Examples of classification of the building materials by their degree of flammability:
degree of flammability A inflammable (bricks, blocks, ceramic tiles, mortar, parging)
degree of flammability B partly flammable (heraklith, lignos, board from basalt felt, novodur)
degree of flammability C1 difficult to ignite (hardwood (oak, beech), plywood, werzalit,
hardened paper)
degree of flammability C2 normal combustibility (softwood (pine, spruce), chipboard,
solodur)
degree of flammability C3 easily ignited (wood fibre boards, polyurethane, PVC, foam rubber,
polystyrene)
The sealing board or protection covering on the protected items must exceed the boiler edge
for at least 300 mm. Also other items from flammable materials must be protected in this way, if
they are placed near the boiler and it is not possible to keep the safe distance.
If the boiler stands on a flammable surface, it must be protected by an inflammable, heat
insulating mat, which exceeds the edge on the side of the feeding door and the ash tray door for
at least 100 mm. All materials of the A flammability degree can be used as an inflammable, heat
insulating mat.
The boiler must be placed in a such way ensuring sufficient space of at least 1 m from the front
and 0,5 m from the left (right) and rear side. It is necessary to leave the space of at least 1 m
above the boiler.
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This space is necessary for basic operation, maintenance and eventual service of the boiler. It is
not allowed to place the boiler in dwelling premises (including corridors).
CAUTION
The items from flammable materials must not be laid on the boiler and within the minimum
distance specified for material type, the permitted (safe) one.
The boiler must be turned off, if there is a danger of fire or explosion due to flammable gases
from paints or materials in the vicinity (e.g. work with painting materials, glues, etc.).
It is not allowed to place the boiler in dwelling premises (including corridors)!
2.4 BOILER CONNECTION TO THE HEATING SYSTEM
The ATTACK WOOD&PELLET must be installed in the system that fulfils the requirements for
quality of the heating water:
Slovak republic: STN 07 7401:1991
Austria: ONORM H5195-1
Germany: VDI 2035
Switzerland: SWKI 97-1
Italy: D.P.R. no. 412
To fill or re-fill the water in the system it is possible to use only the water treated to the values
under the STN 07 7401: 1992. The water must be pure, colourless, without suspendous
substances, oils, nor chemically aggressive ingredients. The water cannot be acidic (pH must be
higher than 7,2).
Callosity of the water must not exceed 1mmol/l and concentration of the Ca²Ѐ must be lower
than 0,3 mmol/l.
CAUTION
If the above mentioned conditions are not adhered to, then the warranty provided by the
manufacturer is void!
Use of antifreeze mixtures
It is not recommended to use antifreeze mixtures as their properties that are not suitable for
operation of the boiler. This particularly concerns decreased heat transfer, large thermal
expansion, ageing, damage of the rubber parts. When it is necessary, it is possible to use the
antifreeze mixture Alicol Termo (producer: Slovnaft Bratislava) – following experience of the
producer there will not come to the decreased safety of usage, nor to the significant influence
on the boiler operation. If this way of protection against freeze is not possible under the
particular conditions and the different antifreeze mixture is used, the warranty does not relate to
the wrong functionality, nor to the eventual faults of the boiler.
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2.4.1 PROTECTION AGAINST CORROSION
The boiler must be connected with a device regulating the temperature of the boiler´s return
connection. It is suitable to use the mixing device Attack-Oventrop (Pic.3), which enables
creation of the separate boiler and heating circuit. Thereby is the boiler protected against
undercooling and the creation of water steam. Acids and tars in the boiler´s feeding chamber are
eliminated.
The Attack-Oventrop device keeps the constant temperature of the return heating water flowing
into the boiler over 65 °C by setting the thermostatic head to the level 5–6.When the individual
thermal regulation mixing valve is used, it is possible to control the temperature of the heating
water independently on the temperature of water in the boiler by setting the flap. The
temperature in the boiler has to be kept in the range of 80–90 °C.
Pic. 3 Device ATTACK Oventrop
CAUTION
If a protection device against corrosion is not intalled in the system or the device does not work
properly, it may lead to creation of an aggressive condensate and thereby boiler damage.
Protection against condensation must be used during boiler operation, otherwise the
warranty is void!
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2.4.2 CHIMNEY
Connection of the appliance to the chimney hole must be always done with in line with local
regulations and the appropriate chimney association. The chimney must generate sufficient
draught and take the flue gas out into the atmosphere under all operating conditions.
Correct dimensions of the chimney are important for correct boiler function, because the
burning, output and boiler life-time are influenced by the draught. The chimney draught directly
depends on its diameter, height and surface finish of the internal wall. It is not allowed to
connect any other appliance to the chimney, where the boiler is connected. Diameter of the
chimney must not be smaller than the connection part on the boiler. The chimney draught must
achieve the precribed values, but it cannot be too high, not to decrease the boiler output and
interrupt the burning (flame). If there is too strong draught, install the throttle flap into the
chimney hole between the boiler and the chimney.
Minimum dimensions of the chimneys:
20×20cm min. height 7 m
20 cm min. height 8 m
15×15 cm min. height 11 m
16 cm min. height 12 m
The exact chimney dimension is defined by the STN 73 42 10. The prescribed chimney draught is
given in the Technical parameters.
2.4.3 FLUE GAS CONNECTION OF THE BOILER
The flue connection must lead into the chimney hole. If it is not possible to connect the boiler to
the chimney hole directly, then the appropriate extension should be as short as possible, of up
to 1 m length, without any additional heating area and it should ascend in direction to the
chimney. It is suitable to insulate the flue connection to achieve the sufficient flue gas
temperature and to prevent the condensation in the chimney. The flue connection must be
mechanically tight (it should be mounted to the boiler and tightly fixed by screws) and tight
against the flue leakage. There must be possibility of the internal cleaning. The flue connections
must to lead through the foreign dwelling or commercial premisses. The internal diameter of the
flue connection must not taper in direction to the chimney. It is not suitable to use the elbow
connectors. There must be a „T“connection of the flue outlet to the chimney, to ensure that the
condensate must leak into the appropriate tray and not into the boiler.
The flue connection must comply with local regulations and only be conducted by authorised
and trained personel.
2.4.4 CONNECTION TO THE ELECTRICITY MAINS
The boiler is connected to the electricity mains of 230V/ 50Hz/16A by an electrical cord with
plug. In the case of need, the power supply cord of the M type must be replaced with an
adequate one by the service organization.
The appliance must be placed in such a way that enables the user to reach the connection plug.
The boiler must be connected to the 16A socket circuit by a circuit breaker (following the STN EN
60 335-1 + A11:1997).
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2.4.5 CONNECTION OF THE EXTERNAL PELLET TANK
The boiler is equipped by a motor for vacuum pellet feeding from an external tank. The external
tank can be placed nearby the boiler or in another room. The max. length of the suction tube is
10 m. The tank can be in the higher position, but not in the lower position than the boiler. It is
recommended to use the ATTACK vacuum tanks for the ATTACK WOOD&PELLET boiler. The
suction tubes ( 50 mm) and the vacuum tank can be ordered as accessories together with the
boiler.
Connection of the suction and blow out tube marked on the rear side boiler as „PELLET IN“and
„PELLET OUT“.
2.4.6 LEFT DOOR VERSION
There is an option of the ATTACK WOOD&PELLET boiler with the left door (door hinges on the
left side). It can be done before the boiler start-up or later, when the boiler is not in service. The
main, upper, middle and bottom door can be turned without need of the any additional tools.
Everything necessary is contained in the boiler. Use the standard tools: cross screwdriver, fork
key of 8–13 mm or nut, allan key of 6 mm, etc. The adjustment has to be done by a trained
worker.
2.4.7 CHOICE AND WAY OF CONNECTION OF THE CONTROL AND SAFETY
ELEMENTS
The boiler is delivered with the basic regulation and control equipment. This equipment must be
completed with other items (not delivered with the boiler) in line with local regulations, that
have to be installed in the heating circuit – particularly the following ones: safety valve (Pic. 4)
against exceeding the permitted pressure in the heating system (prescribed value: 2,5 bar), valve
of the boiler aftercooling loop to take the excessive heat from the boiler into the waste and
deaeration valve for the correct boiler function. The volume of the expanse vessel in the system
has to be defined by a designer of the heating system according to the system design and local
regulations. The electrical installation related to the additional boiler equipment has to be done
by a specialist and following the valid regulations.
DANGER
The heating system must be equipped with a safety valve against
exceeding the pressure in the boiler (2,5 bar). This valve should
be placed on the flow connection of the boiler, always installed in
front of the boiler closing valve (or in front of the Oventrop –
scheme 1). If the safety valve is not functional, the excessive
pressure will not be eliminated and it may cause an explosion
of the boiler.
Pic. 4 Safety valve against the overpressure
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Boiler protection against overheating
Every wood gasifying boiler must be fitted with a functional aftercooling circuit. The appropriate
valve ensuring this function can be ordered as an accessory. On the pic. 5 you can see the correct
installation of the valve of the aftercooling circuit.
DANGER
Following the norm EN303-5, the aftercooling circuit against overhetaing must not be
used for other purpose than the boiler protection against overheating.
Pic. 5 Connection of the thermostatic valve to the aftercooling loop
The valve must be permanently opened at the cold water inlet into the boiler aftercooling
circuit. The aftercooling circuit must be connected to the functional distribution of the cooling
water (e.g. to the distribution of the cold water in the water supply network) with the
temperature of 10–15 °C and operating overpressure of 2–6 bar, ensuring the safe operation
even by a power failure.
The thermostatic valve at the outlet of the aftercooling circuit with the sensor placed in the rear
side of the boiler protects the boiler in the following way. If temperature of the water in the
boiler exceeds 95 °C, the valve fills the aftercooling circuit with the water from the water supply
network to absorb the excessive heat. For the case that the boiler gets overheated and the
thermostatic valve is open, it is necessary to ensure the permanent outtake of the warm water
from the aftercooling circuit into the waste. Functionality of the aftercooling circuit and the
thermostatic valve can be checked manually, by the manual button of the thermostatic valve.
DANGER
If the circulation of the cooling water through the aftercooling circuit is not ensured, when
the thermostatic valve is open, there is a danger of the boiler damage! The warranty is not
valid in such a case.
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2.4.8 CONNECTION TO THE ACCUMULATION TANKS
The accumulation tanks are connected to be warmed and the accumulated heat is continually
used according to the requirements of the heated space. When the boiler operates at full output,
the accumulation tanks are heated to 80–90 °C. Usage of the accumulation tanks together with
the boiler ATTACK WOOD&PELLET brings several advantages. The main advantages are:
prolonged life of the boiler, cleaner operation, minimal creation of acids and condensate, smaller
frequency of the fuel loading, lower probability of the boiler overheating and fuel saving.
The recommended volume of the accumulation tank for the boiler ATTACK WOOD&PELLET 25 is
2.000 l (the min. volume is 1.250 l). By full load of the hardwood (i.e. 6 hours of operation at full
output of 25 kW), the boiler produces 150 kWh of energy. This is adequate to the loading of the
2.000 l accumulation tank from 20 °C to 80 °C, if there is no other energy consumption. Thereby
it is necessary to consider the boiler usage and operation as well, when you are choosing the
accumulation tank: by the accumulation tank of 2.000 l it is necessary to load the full chamber,
by 1.000 l there is half of the chamber to be loaded (if there is no energy outtake from the tank).
Example 1:
The external temperature of environment is -5 °C and the heat loss of the building is 10 kW. The
boiler output by full operation is 25 kW. There is an accumulation tank of 1.250 l, that is
discharged (its upper and bottom temperature is 20 °C). As the heating system (to cover the heat
loss) takes 10 kW from the accumulation tank and the boiler has the output of 25 kW, the
accumulation tank is heated by the remaining 15 kW. The output of 15 kW, by the full load of
hard wood and during the 6 hours of operation, creates the energy of 90 kWh. This energy heats
the accumulation tank from 20 °C to 62 °C despite of the fact, that the 10 kW are being taken.
This is a safe and economical operation, when the heat is not taken into the waste (the boiler
was cooled down by the aftercooling circuit). The boiler is able to cover the heat loss for 15
hours just by a single load of the wood.
Example 2:
The external temperature of the environment is +3 °C and the heat loss of the object by this
temperature is 5 kW. The boiler output at full operation is 25 kW. There is an accumulation tank
of 1.250 l, that is discharged (its upper and bottom temperature is 20 °C). As the heating system
(to cover the heat loss) takes 5 kW from the accumulation tank and the boiler has the output of
25 kW, the accumulation tank is heated by the remaining 20 kW. The output of 20 kW, by the full
load of hard wood and during the 6 hours of operation, creates the energy of 90 kWh. This
energy heats the accumulation tank from 20 °C to 82 °C despite of the fact, that the 10 kW are
being taken. This is a safe and economical operation, when the heat is not taken into the waste,
but if the heat loss was smaller, the boiler could get overheated, because it would not be cooled
down. In such case it would come to activation of the aftercooling circuit and the excessing heat
would be taken into the waste. In case of the constant heat loss of the object (5 kW), the charged
accumulation tank would cover the heat loss approximately for the next 24 h. It means that by
a single load of wood and under the above mentioned conditions it would be possible to cover
the heat loss of the building for 30 hours.
Thereby it is very important to load just the amount of wood, adequate for heating the
accumulation tank and not to overheat it, because the excessive heat would be taken into the
waste unused. Such operation would not be economical and the safety element, the
aftercooling circuit would have to be activated.
The bigger volume of the accumulation tank decreases the risk of overheating and the
frequency of loading the wood.
17
Note:
The above mentioned fact is relevant by the operation with WOOD.
By the operation with PELLETS it is not relevant, as the boiler does not have to be
connected to the accumulation tank, if ONLY PELLETS would be used.
Standardly delivered accumulation tanks ATTACK*
AK AS HR HRS
TUV
TUVS S SS
300 300 — —
300
300 — —
400 400 — —
400
400 — —
500 500 600 600
500
500 500 500
800 800 800 800
600
600 800 800
1000 1000 1000 1000
800
800 1000 1000
1500 1500 1250 1250
1000
1000 1250 1250
2000 2000 1500 1500
1250
1250 1500 1500
2500 2500 2000 2000
1500
1500 2000 2000
3000 3000 — —
2000
2000 — —
4000 4000 — — — — — —
5000 5000 — — — — — —
AK – standard accumulation tank intended for the accumulation of energy of the heating water
AS –standard accumulation tank intended for the accumulation of energy of the heating water,
equipped with a coil for connection of the solar panels
HR – combined accumulation tank for accumulation of energy of the heating water and the
domestic hot water preparation
HRS – combined accumulation tank for accumulation of energy of the heating water and the
domestic hot water preparation, equipped with a coil for connection of the solar panels
* The volume necessary for the accumulation of energy can be covered by one or by several
accumulation tanks. The accumulation tanks can be connected together to create the sufficient
volume of water for accumulation. Thereby, if you decide for a volume of 2.000 l, it is possible to
use one tank of 2.000 l or two tanks of 1.000 l connected together. The required way of
connection is given in the chapter „Recommended hydraulic schemes of boiler connection“.
18
2.4.9 RECOMMENDED HYDRAULIC SCHEMES OF BOILER CONNECTION
Pic. 6. Hydraulic connection of the boiler into the heating system
1 – boiler, 2 – safety valve, 3 – deaeration valve, 4 – Attack Oventrop, 5 – accumulation tank
Attack AK or HR, 6 – distributor, 7 – tank for domestic hot water, 8 – direct heating circuit, 9 –
mixing heating circuit
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