ATMOS C 15 S upr

Product detailed description

The ATMOS C 15 S upr is commonly integrated into central heating systems in residential and light commercial buildings requiring dual-fuel flexibility. Installers typically encounter this model in scenarios where seasonal fuel switching is preferred or where retrofitting an existing solid fuel boiler with a pellet burner is economically viable. The unit supports both manual and automated fuel feeding when equipped with a pellet burner and integrates well with heat storage tanks and circulation circuits.

This boiler is suitable for use in combination with various types of thermal distribution systems, including radiators and underfloor heating. The design allows for adaptation to different chimney configurations and enables efficient combustion of solid fuels while maintaining environmental compliance. The installation process requires careful attention to air flow, fuel feed geometry and control module positioning to ensure stable operation over time.

Technical parameters

Water volume	37 L
Boiler weight	276 kg
Fuel hopper volume	45 dm³
Required chimney draft	16 Pa
Energy efficiency class	A+ (pellets) / B (coal)
Combustion class	5
Boiler output on pellets	3–12 kW, 90.1% efficiency
Boiler output on coal	16 kW, 90.4% efficiency
Code	C15S UPR
Brand	Atmos

The technical parameters define the boiler’s operational range and integration potential. The 3–12 kW output when using a pellet burner allows for fine-tuning of heat supply, while the 16 kW rating with coal ensures sufficient capacity for larger spaces. The 37 L water content indicates moderate thermal inertia, and the 45 dm³ hopper supports extended operation between refills. The required chimney draft of 16 Pa must be verified during installation to prevent backfiring or inefficient combustion.

Installation and connection

Installers should begin by verifying chimney draft using a manometer to confirm that the 16 Pa requirement is met. The boiler is supplied with two AD03 modules for controlling the exhaust fan and circulation pump, which must be connected to the power supply and boiler control unit according to the wiring diagram provided. Fuel feed ducts must be at least 2 m long to ensure proper alignment with the upper door opening for the pellet burner module. A left or right-opening configuration must be specified at the time of order due to directional differences in flue gas path and control panel placement. Key checkpoints include ensuring that the boiler base is level, that all flange connections are sealed with appropriate gaskets, and that the exhaust fan is not obstructed by nearby structures. Common installation errors include incorrect orientation of the ash pit, misalignment of the fuel feed inlet, and failure to verify chimney slope and height. The boiler must be grounded and connected to a stable electrical supply to support automatic functions such as ignition and shutdown cycles.

Compatibility and accessories

The ATMOS C 15 S upr is compatible with standard solid fuel systems and can be retrofitted with the A25 pellet burner for automated operation. Essential accessories include the DA screw conveyor (available in various lengths) and a pellet storage tank of appropriate size to match the 45 dm³ hopper capacity. Two temperature sensors (TV and TS) are included for monitoring accumulator tank conditions, and an additional TK sensor is provided for boiler temperature regulation. The boiler does not include the burner module in its standard delivery, so it must be ordered separately. The AD03 control modules are essential for managing fan and pump operations and must remain connected throughout the boiler’s operational cycle. Additional components such as expansion vessels and safety valves must be selected based on the system’s overall hydraulic balance and pressure requirements.

Technical background for designers

The boiler operates via a combustion chamber constructed from 3–8 mm thick steel plates, welded for structural integrity. The upper chamber features a door with an aperture for inserting the pellet burner, while the lower section contains a cast iron grate for ash removal. The ceramic refractory lining in the lower chamber enhances heat retention and promotes complete combustion of all combustible materials. The combustion process is supported by an exhaust fan controlled via the AD03 module, which adjusts airflow based on temperature readings from the TK and TS sensors. The boiler’s high efficiency (90.1% for pellets and 90.4% for coal) is achieved through precise control of air-to-fuel ratios and staged combustion. Designers should consider the boiler’s 276 kg mass when planning foundation reinforcement and access routes for maintenance. Integration into a closed-loop system requires a return line with sufficient flow rate to avoid overheating. The cooling loop built into the boiler prevents damage from excessive temperatures, particularly during periods of low heat demand. The design also facilitates modular expansion, allowing for future upgrades such as increased automation or integration with solar thermal systems.

Service and operation

Routine maintenance includes checking the exhaust fan for blockages, inspecting the grate for wear, and verifying the integrity of the refractory lining. Ash removal should be performed manually from the lower chamber at intervals of 7–30 days, depending on usage. The hopper should be inspected regularly for signs of corrosion or blockage, especially when switching between fuel types. The automatic shutdown function engages after the fuel has burned out, preventing unnecessary energy consumption and prolonging component life. The boiler should be drained and winterized during long periods of non-use to prevent internal freezing. No specific service intervals are stated, but annual inspections are recommended to ensure continued compliance with combustion standards and safety regulations.

Frequently asked questions

Can the ATMOS C 15 S upr be adapted for fully automatic operation?
Yes, by fitting the A25 pellet burner and DA conveyor, the boiler can operate automatically with minimal user intervention.

What is the minimum length required for the fuel conveyor?
The conveyor must be at least 2 m long to align correctly with the boiler’s upper door opening.

Is the boiler available in left- or right-hand configurations?
Yes, the left- or right-hand door orientation must be specified at the time of order in the notes field.

Does the boiler require a separate expansion vessel?
It depends on the system design. An expansion vessel should be included if the total water volume exceeds the boiler’s internal capacity of 37 L.