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ATLAS Pellet Boiler, 65K-120K BTU
$3,199.00
$2,879.10
Shipping
$544
Free
- Your heating bill will noticeWood pellets cost a fraction of oil or gas — and the Unica burns them at over 93% efficiency. That combination hits your wallet in the best possible way.
- One stove, whole houseThe water jacket pushes heat to every room — radiators, radiant floors, fan coils, even your hot water tank. One fire does it all.
- Fuel you can feel good aboutWood pellets are renewable, low-emission, and sold at farm stores and hardware chains across North America. A cleaner way to stay warm.
- Built to stay cleanLift the top cover, screw in the handle, move it up and down. Two minutes, once a week. That's all the maintenance this stove asks for.
- Real people, real answersNot a chatbot. Our hydronic HVAC team picks up the phone and helps you get the system right — before the install and after.
Product details
ATLAS Pellet Boiler – High-Efficiency Water-Jacketed Pellet Boiler
The ATLAS Pellet Boiler is a high-efficiency pellet boiler designed as a compact, powerful, and aesthetically striking heating solution for residential homes and light commercial spaces. With up to 94% thermal efficiency, an integrated water jacket, automated fuel modulation, and smart remote control options, the ATLAS boiler delivers dependable central heating performance directly into your property.
Key Benefits
- Operates at up to 94% efficiency to maximize wood pellet fuel economy.
- Available in sizes 65K BTU and 120KBTU.
- Internal fuel bunker holds up to 99 lbs of pellets for extended autonomous heating periods.
- Electronic system dynamically self-modulates pellet feed and airflow based on thermostat demand.
- Embedded controller supports daily, weekly and weekend automated start/stop timers.
- Hardwired protection loops include water overheating sensors, system pressure tracking and return-flame sensors.
- Outfitted with an ultra-fast quartz igniter for swift flame starts and a digital fan speed encoder for stable draft pressure.
- Designed with tool less access including quick-release side panels and a spacious, slide-out ash tray compartment.
Specifications
- Heating Capacity: 65 KBTU / 120 KBTU
- Efficiency Rating: Over 94%
- Maximum Water Temperature: 194°F (90°C)
- System Operating Pressure: 30 PSI
- Exhaust Vent Pipe Flue: 4"
- Fresh Combustion Air Inlet: 2 3/8” (65K BTU) / 3” (120K BTU)
- Fuel Type: Pellet Dia. 1/4" to 5/16"
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Electrical supply: 120V 60Hz
Customer Success Stories
The Apollo heat pump system is very efficient, quiet, and easy to install. It stands out for its clear design, well-organized components, and advanced features like a touchscreen and remote monitoring through an app. It also allows precise temperature control and includes an electric backup for very cold conditions. Overall, it's a reliable and practical system.
Heats my home nicely and economically. The cold weather does not seem to affect the pump. Overall I'm very happy with the system. The techs have been very helpful whenever I have had questions regarding installation, etc.
Since installing the Apollo heat pump, our energy bills have plummeted. It pulls heat right out of the air outside, even when it's freezing, and uses a fraction of the electricity our old system did. It's incredibly efficient
I was skeptical about a heat pump in our cold climate, but the Apollo proved me wrong. It consistently delivers strong, comfortable heat to our entire home, even during the deepest winter freezes. It's a truly robust system
Upgrading to the Apollo air-to-water heat pump was the best decision for our home. It integrated perfectly with our existing radiant floor heating. It runs quietly outside and provides perfectly even, comfortable heat inside
You can tell just by looking at the Apollo unit that it's built to last. It handles the elements outside without a problem and operates surprisingly quietly. It gives us total peace of mind knowing we have such a dependable system
Maximizing Efficiency with Apollo Heat Pump
Economical performance that isn't affected by low temperatures.
Reliable Heating in Cold Weather
Economical performance that isn't affected by low temperatures.
Incredible Energy Savings
Slashing utility bills with high-efficiency air-to-water technology
Reliable Heat, No Matter the Weather
Powerful performance that stands up to freezing temperatures
The Ultimate Home Heating Upgrade
Seamlessly integrating with existing radiant or hydronic systems
Built to Weather Any Storm
Heavy-duty construction for years of reliable, quiet operation
Maximizing Efficiency with Apollo Heat Pump
Reliable Heating in Cold Weather
Incredible Energy Savings
Reliable Heat, No Matter the Weather
The Ultimate Home Heating Upgrade
Built to Weather Any Storm
Mareli Systems Unica
Main Features
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Up to 94% Thermal Efficiency
Advanced heat exchanger design captures more heat from every pellet, delivering exceptional efficiency, lower fuel consumption and reduced heating costs throughout the season.
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Automatic Combustion Management
An intelligent control system continuously adjusts fuel feeding and combustion settings to maintain optimal performance, consistent comfort, and maximum energy efficiency.
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Spacious Ashtray Compartment
The large capacity ash collection compartment reduces cleaning frequency and simplifies routine maintenance, allowing longer operating periods between service intervals.
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Easy-to-Use LCD Display
LCD control panel provides quick access to temperatures, operating modes, schedules and system information for simple day-to-day operation.
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Weekly Programmable Schedule
Customized daily and weekly heating schedules to automatically start and stop the boiler, improving comfort while reducing unnecessary energy consumption.
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Advanced Safety Monitoring
Multiple sensors continuously monitor water temperature, pressure, airflow and combustion conditions to ensure safe, reliable, and worry free boiler operation.
Capacity: 61-120K BTU/h
Provides enough continuous warmth to comfortably heat medium to large homes or commercial spaces.
Hopper Capacity: Up to 99 lbs
Holds up to 99 pounds of wood pellets, giving you days of continuous, automated heating before needing a manual refill.
Max Water Temperature: 194°F
This is the highest safe heat the internal water can reach, ensuring piping-hot water flows reliably to your radiators or underfloor heating loops.
Electrical Supply: 230V 50Hz
Uses a standard 230-volt power supply to safely run its automatic starter, electronic control screen, internal pumps and exhaust fans.
Technical specifications
All values from Mareli Systems Unica user manual rev. 2.0. Output-specific values shown as a range across the 8/12/15/18/24/30 kW models.
| Maximum output | 8 / 12 / 15 / 18 / 24 / 30 kW |
|---|---|
| Heated area (0.035 kW/m³) | 220 / 340 / 430 / 510 / 680 / 860 m³ |
| Water jacket capacity | 16 / 30 / 30 / 41 / 41 / 48 L |
| Space heating output | 0.9 / 1 / 1 / 2 / 3 / 4 kW |
| Max water temperature | 90 °C |
| Working pressure | 0.5 – 2.0 bar |
| Energy conversion efficiency | >93% (8/12/15 kW), >94% (18/24 kW), >93% (30 kW) |
| Fuel type | Wood pellets Ø6–Ø8 mm (EN Plus A1/A2 / ISO 17225-2) |
| Pellet bunker volume | 22 / 30 / 30 / 39 / 39 / 45 kg |
| Exhaust gas pipe | Ø80 mm |
| Fresh air pipe | Ø60 mm (8–24 kW) / Ø76 mm (30 kW) |
| Chimney draft | 12 Pa (recommended 12–20 Pa) |
| Electrical supply | 230 V / 50 Hz |
For comparison tables across all six output sizes, or for installation-specific data, refer to the full user manual linked in the Documents tab.
Product documents
Unica Pellet Stove — User Manual rev. 2.0
Full installation, operating, cleaning, error codes, spare parts, and wiring diagram for the Unica 8/12/15/18/24/30 kW.
