Compact pellet boilers

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Description

Pellet boiler D15PX and D20PX

Compact automatic pellet boilers

ATMOS D15PX and D20PX hot-water boilers are designed for convenient heating of family houses, holiday homes and other buildings with pellets. Boilers are supplied as a complete device with a built-in conveyor, pellet reservoir with the volume of 175 l and ATMOS A25 pellet burner.
Their compact solution enables installation in small boiler rooms.


Boiler construction

are designed for electronically controlled burning of pellets with automatic ignition of fuel. The pellet burner is incorporated into the front part of the boiler in the door of the lower combustion chamber. This chamber is also used as an area for ash. A tube exchanger with a segmental decelerators with function of rough (operation) cleaning without necessity of taking them out is placed in the back part of the boiler.

The boiler body is made as a weldment of steel sheets with the thickness of 3 - 6 mm. Insulated from the outside with mineral felt located under the sheet-metal covers of the outer boiler jacket.
A fuel reservoir from which the pellets are transported to the burner with a screw conveyor is located in the top part. Fuel metering is controlled fully automatically. In the fron part of the boiler there is a panel with the main switch, the switch of the pellet burner (L2), an operation (control) thermostat, a safety thermostat, a thermometer and a 6.3 A fuse.
Boilers DxxPX is equiped with exhaust fan.
The boiler is not equipped with a cooling loop against overheating as thanks to the small quantity of fuel in the burner there is no risk of boiler overheating in case of a power supply failure.

 

  

D15PX and D20PX boilers meets 5th emission class (Energy efficiency class A+), Ekodesign.

 

Advantages of special compact boilers ATMOS with new construction

  • Compact dimensions for small boiler rooms
  • All in one – boiler, pellet reservoir, conveyor anf burner
  • Large ceramic burning chamber
  • Exhaust fan – operation without any problems, ash cleaning without dust, boiler room without smoke
  • Tube heat exchanger with possibilities of operation cleaning
  • High efficiency over 90 %
  • High comfort of heating – completely automatic boiler operation
  • Comfortable ash removing – easy cleaning only from the front
  • Small size and low weight
  • Possibility to equip the boiler with pneumatic pellet feeding
  • Possibility to equip the burner with pneumatic cleaning system
  • Ecological burning - boiler class 5 - ČSN EN 303-5, ECODESIGN 2015/1189

 

Opened pellet reservior with volume 175 l
Control panel and connecting pipe
from the conveyor

 

Combustion chamber with ceramic shaped bricks
Opened burning chamber with burner
ATMOS A25

 

Tube heat exchanger with segmental decelerators
Exhaust fan and flue gas neck

 

 

Burner

Pellet burner ATMOS A25

Pellet burner using for boilers D15PX and D20PX

Pellet burner ATMOS A25

Specified fuel: good quality pellets with 6 – 8 mm diameter, 5 - 25 mm lenght and 16 - 19 MJ.kg-1 caloric power (white pellets).

The burner screen: used to display the current status of the burner and adjusting her functions.

Burner control: with an AC07X electronic control unit that controls the operation of the external conveyor, two ignition spirals and the fan in accordance with requirements of the boiler and the heating system. The electronic system is rotected with the safety thermostat of the boiler, safety thermostat at the pellet supply to the burner, the fan speed transducer and the flame sensing photocell.The operation of the burner is indicated on the electronic control display.
Burner in version for boilers DxxPX contains moreover additional module AC07X-C - (R5, R6) to controle pneumatic cleaning system for pellet burner or other possible aplications.

Ignition of fuel: automatic assisted by two electric ignition spirals.

Basic functions of burner:
Spare outputs R and R2 for control of exhaust fan of the boiler and pump in the boiler circuit (connected from the production)
The possibility of using two spare outputs R5 and R6 for various applications
The possibility of the involvement of four different sensors TS, TV, TK and TSV
TK - boiler temperature sensor (connected from the production)
TSV - flue gas temperature sensor (connected from the production)
TS - temperature sensor on the tank bottom
TV - temperature sensor on the tank top

  • control of boiler fan from burner with the help of the spare output (R- reserve) (connected from the production) 
  • control of boiler pump from burner with the help of the spare output (R2- reserve) (connected from the production)
  • burner controlling it in accordance with two temperatures (sensors) on the buffer (accumulation) tank

Fuel feeding: for boilers DxxPX is designed special auger conveyor DRA25 which is inbuilded directly inf the boiler. This conveyor is controlled from electronic regulation of burner and dose the fuel from the reservoir  in to the burner.

 

Instalation

The prescribed solution consists in the installation of the boiler with Laddomat 22, or a thermoregulation valve, which allows you to create a separated boiler and heating (primary and secondary) circuit to ensure the minimum temperature of return water to the boiler of 65 °C. The higher the return water temperature is, the lower you will keep condensation of tar and acids that are harmful for the boiler body. The output water temperature of the boiler must be permanently in the range of 80 - 90 °C.
Another variant is connection of the boiler with a three-way mixing valve with an actuator controlled from the electronic controler (e.g., ATMOS ACD01, ACD03, ACD04) to keep minimum temperature of the water returning to the boiler (65 - 75 °C).

We recommend you to always connect the D15PX and D20PX boilers with an buffer tank with the volume of 500 to 1000 l. When connecting the boiler with the buffer (accumulation) tank, the boiler is controlled best according two TS and TV sensors located on the tank. To control the burner according two temperatures on the buffer (accumulation) tank it is necesary to place two KTF 20 sensors (TV and TS sensors) on this tank.

 

Laddomat 22 and thermoregulatory valve
DxxPX boiler connection with buffer tank

 

D15PX, D20PX boiler connection with buffer tank to
control the burner by TV and TS sensors and boiler pump
control from the burner by boiler temperature (sensor TK) from the burner A25

 

D15PX, D20PX boiler connection with buffer tank and regulation ACD01

 

Operation anad regulation

The boilers are delivered to the user with the basic control of the boiler output, which complies with the requirements for the heating comfort and safety. The control ensures the required output temperature of the boiler water (80 - 90 °C). Boilers are equipped with connector for connection of the pump in the boiler circuit and functions for its control directly from the regulation of the ATMOS A25 burner.

D15PX and D20PX boilers are from the serial production equpied with sensors of boiler temperatre TK and flue gas temperature TSV. The TK sensor placed in boiler pocket, TSV waste gas sensor build in boiler waste gas duct and all connected directly to the burner. ATMOS A25 pellet burner directly control exhaust fan of the boiler (R) and pump in boiler circuit (R2). R2 output is connected in serie with TČ70 °C pump thermostat for pump in boiler circuit.

When recomand connecting of the boiler with the buffer (accumulation) tank, the boiler is controlled best according two TS and TV sensors located on the tank. Switching of pumps in the system circuit in this case does not depend on the boiler temperature and therefore it is solved according to potential requirements of the system.

 

Control panel with standard regulation


Each boiler can be fitted with Equithermal regulation ATMOS ACD 01 for control of the heating system depending on the outdoor temperature, room temperature and time.  

 

Refuelling

The boiler is equipped with an integrated fuel reservior that must be refilled in the interval from 1 to 3 days.

If the alarm message ALARM PELLETS - REFILL PELLETS appears on the burner display, pellets must be added to the fuel tank. Open the tank cover in the top part of the boiler and add pellets. When the pellets are added, it is not necessary to pump the pellets to the conveyor! The boiler is equipped with a special function against its full emptying.

In the case that the refuelling interval is too short for your needs, an extensions with the height of 200 mm (65 l) (code: S1233) or 300 mm (95 l) (code: S1234) can be added (to buy) to the reservior of the boiler. Extensions can be folded together. It is, however, necessary to buy additional step ladder for convenient refuelling according to all valid safety regulations.
However, additional buying of the pneumatic pellet feeder ATMOS APS 250 SPX for convenient automatic refuelling from any silo, e.g., for the whole season (textile silo, separate room), is the ideal solution.

 

Example of standard refuelling with pellets
from 15 kg bags.
Boiler with the pneumatic pellet feeder
ATMOS APS 250 SPX

 

Reservior extensions for boilers DxxPX
DxxPX boiler with reservior extension - 300 mm

 

Boiler room with the DxxPX boiler and a large built-in pellet storage
with multipoint sucking of pellets with pneumatic feeder ATMOS APS 250 SPX

 

Boiler cleaning

The burner and the boiler must be cleaned regularly and thoroughly once every 1 to 14 days depending on the quality of pellets and the output setting.

The boilers are able to burn only good quality white pellets from soft wood without bark ø 6 - 8 mm, lenght 10 - 25 mm with heating power 16 - 19 MJ.kg-1. Boilers are not able to burn pellets with high sintering in the burning chamber of the burner. In such case it is needed to clean the burning chamber in period one a day. The pellet burner ATMOS A25 can be equipped with pneumatic cleaning of the combustion chamber. It will be appreciated especially by those using lower quality pellets forming certain agglomerates.

Comfortable ash removing – easy cleaning only from the front. Remove the ash from the whole cleaning chamber with the half-round ash pan (accessory of the boiler). Insert the ash pan into the boiler to the end, push the ash into the ashtray by thrusting it into the rear wall and remove the ashtray. Never leave the ash pan in the boiler! 

D15PX and D20PX boilers are equpied with function of operation cleaning of the tube exchanger. Use the handle on the cleaning lid in the rear part of the boiler hidden under the cover for operation cleaning of the tube exchanger and decelerators. By repeated pulling out and releasing of the handle the ash is knocked out from the decelerators and the tube plate walls are scraped off.

 

Example of ash removal with the ash pan
 
Example of operation cleaning
of the tube heat exchanger

 

Technical informations

 

Captions for the diagrams of the boilers

1. Boiler body 16. Main switch (red) (code: S0092)
2. Cleaning door (code: S0459) 17. Control (boiler) thermostat (code: S0021)
3. Pellet Burner ATMOS A25 - (code: H0044) 18. Burner switch (black) (code: S0102)
4. Control panel 19. Safety thermostat (code: S0068)
5. Conveyor 20. Fuse T6,3A/1500 - typ H
6. Door filling - Sibral - large with hole for the burner (code: S0266) 21. Cleaning lid cover
7. Door gasket, 18 x 18 mm (code: S0240) 22. Exhaust fan
8. Closure (code: S1047) 23. Condenser for exhaust fan - 1μF
9. Insulation under the burner (code: S0164) 24. Cleaning lid of the rear drain
10. Fuel reservior (tank) 175 l 25. Reservoir cover
11. Tube heat exchanger 26. Burner connecting hose – length 550 mm, Ø 60 mm
12. The decelerator with a cleaning pull rod and handle K flue gas neck
13. Heat-resistant fire brick – bottom of the combustion chamber L water outlet from the boiler
14. Heat-resistant fire brick – screen M water inlet to the boiler
15. Thermometer (code: S0041) N socket for the filling tap


Boiler dimensions

Boiler type D15PX D20PX
A 1411 1411
B1 1145 1145
B2 1447 1447
C 674 674
D 1213 1213
E 150/152 150/152
F 140 140
G 1150 1150
H 166 166
CH 166 166
I 6/4” 6/4”

 

Technical data

Boiler Type D15PX D20PX
Boiler output kW 4 - 15 6 - 20
Heat-delivery area m2 1,9 1,9
Fuel shaft volume (pellet reservior (tank)) dm3 175 175
Filling opening dimensions mm 542x480 542x480
Prescribed chimney draught Pa 15 16
Max. working overpressure of water kPa 250 250
Boiler weight kg 345 345
Exhaust pipe diameter (flue gas neck) mm 150/152 150/152
Ingress protection of the electric part IP 20
El. power input - on startup
                      - in operation
  572/1092
92
572/1092
92
Boiler efficiency % 92,7 91,5
Boiler class   5 5
Energy efficiency class   A+ A+
Flue gas temperature at the nominal output (pellets) °C 118 142
Weight flow of flue gas at the nominal output (pellets) kg/s 0,011 0,015
Prescribed fuel (preferred)   high-quality pellets with the diameter of 6 - 8 mm and the calorific value of 16 - 19 MJ/kg-1
Average consumption of fuel - pellets - at the nominal output   3,6 3,6
Water volume in the boiler l 76 76
Hydraulic loss of the boiler mbar 0,20 0,20
Minimum volume of the buffer tank l 500 500
Mains voltage V/Hz 230/50
The prescribed minimum temperature of return water in operation is 65 °C.
The prescribed operation temperature of the boiler is 80 - 90 °C.