Boiler Systems

Propell central heating systems

  • Fully automated
  • Simplified programming
  • Exceptional efficiency
  • Seamless integration
  • Safe operation

Propell pellet boilers for commercial and industrial heating applications range in output from 500,000 BTU to 10,000,000 BTU/h—generally buildings larger than 10,000 ft 2 , unless significant hot water is being used for process or domestic needs.

Propell systems are not only highly efficient but also fully automated, requiring only periodic inspection and maintenance. A proprietary, Web-based programmable control provides the “brains” of the system, allowing for more precise control and higher efficiency than the vast majority of fossil-fuel-based boilers.

System description

Computerized control

Propell’s sophisticated controls operate far more efficiently than all but the most advanced oil, propane, or natural gas systems. Our heating systems not only operate with clean, renewable pellet fuel but also maximize operating efficiency with ”intelligent” controls, which are capable of variable modulation. In contrast to a simple on/off controller that features only high and low set points (a typical boiler), our controls rarely overshoot the set temperature, and they even monitor critical factors in predicting heating demand, like outdoor temperature and time of day. If your organization has a spike in heating demand, such as the morning domestic hot water needs of a hotel, the system will store enough hot water in advance to meet the increased demand, and then slow down before demand subsides.

Fuel delivery and storage

Unlike other forms of biomass, pellet fuel is highly refined and therefore easy to transport, store, and handle. There are several options when choosing your pellet storage system, the most common being a silo. Other options include a bin or underground bunker with a “V” bottom. For most commercial applications, fuel storage is designed to allow for a minimum capacity of a full delivery trailer’s worth of pellets, or approximately 24 tons. Smaller storage and delivery options are available.

Delivery of pellets is essentially the same as any liquid fuel, such as oil—but without the associated safety hazards. Deliveries are timed to ensure that you never run out of pellets, and the fuel is transferred quickly into your silo via a fully enclosed pneumatic tube or auger.

Fuel feed system

Pellets are delivered to the burner via automated, variable feed screws. The control system monitors numerous factors to determine the feed rate and optimize system efficiency. The fuel feed system also has fire protection monitors and redundant fire suppression to ensure safety at all times, even if power and external water supplies are lost.


The burner has automatic ignition, and combustion is controlled by primary and secondary variable speed blowers, ensuring extremely high temperatures (over 2000°F) and complete combustion of gases. Unlike most fossil fuel systems, our burners are capable of infinite modulation, or “turn-down” to 20% of nominal power. This significantly increases overall system efficiency, allowing the system to increase and decrease its heating output without shutdown and restart. Burner construction is durable, with a welded steel water-jacket, ceramic fire chamber, and cast iron grate.


The boiler’s job is to efficiently transfer the hot gas produced by the burner into the water that will distribute heat to the facility or process. Our boilers are produced with welded steel water-jacket construction with vertical heat exchangers for highest possible operating efficiency. They are equipped with automatic cleaning systems, which require only periodic inspection and maintenance. A variable speed exhaust fan and cyclone work in concert with the burner’s combustion fans to ensure clean, efficient operation.

Ash handling and exhaust

Pellets have remarkably low ash content (0.5-1.0%), resulting in a minimal, non-hazardous byproduct. In fact, it takes over 3 tons of pellets to produce 1 cubic foot of ash! Made from 100% wood, pellets create a safe ash that is often used as fertilizer (to achieve pH balance) in the agricultural industry.

Propell systems have automated internal cleaning and ash removal systems, delivering ash via auger to a sealed bin for easy handling and disposal. If you don’t have a value-added use for the ash, Propell can arrange for removal on an ongoing basis.

The high combustion efficiency of Propell’s heating systems means lower operating cost combined with the lowest possible emissions and exhaust temperatures. A variable speed fan and cyclone work in concert with the combustion control system for optimal performance.