E500 Commercial Wood Boiler

The E500 is a wood gasification boiler.  It comes in both carbon steel and stainless steel and can heat up to 20,000 square feet. It has been manufactured in Pennsylvania since 1981.

The Wood Gun series of boilers are some of the most fuel-effective choices out there. While standard boilers waste two-thirds of your fuel’s energy potential, the Wood Gun catches and utilizes 66% more burning matter, converting it all into clean, consistent heat.

The Wood Gun was designed to lessen the work involved in general maintenance…

All Wood Guns can take on whole logs of up to 10 inches in diameter. The Wood Gun relieves you of a good amount of log-cutting job (length of the firebox is shown below); the ability to use logs of up to a maximum of 30% moisture, saves on wood drying time; and, due to our trademark Exhaust Scrubbing innovation, the Wood Gun’s heat exchanger is able to clean itself—so the only weekly cleaning you’ll have to do is dump the ash.

The Wood Gun series can be utilized with any heating system (water-based, steam, forced-air).

Each Wood Gun can be ordered with an automatic feed option which enables you to heat up an assortment of wood particle fuels, varying from sawdust and wood chips to shavings, pellets, and other wood wastes¹. Additionally, with an AHS automatic feed system, if you would also want to use logwood in the unit, you can change the firebox slightly to accept logwood, it takes about 15min.

How it functions

In a typical setting, particle fuel is transported by a fan or other ways to a container. Fuel is transported on request through an auger and a bin agitator which gives a uniform discharge of material. A photoelectric sensor (3) supervises the height of the fuel in the fuel chamber (4) and turns on the feed system instantly.

Two main safety features of the AHS automatic feed system are the rotary air-lock (1) and the fuel valve (2). As it is essential to regulate maximum control over the airflow of the boiler system to control burning and permit off cycle, it is essential that no air be able to penetrate into the boiler from the top feed opening. This is achieved using a rotary valve, a gadget that utilizes the same concept as a department store’s spinning door. The fuel valve is a device that separates the fuel that is being burned in the fuel chamber and the fuel that is in the loading system, preventing the ignition of the fuel in the loading system.

The Wood Gun combustion chamber (5) is situated below the fuel chamber and is comprised of cast refractory sections which are placed end to end to make up the three tunnels. This material has properties and texture similar to firebrick and helps to create the environment needed to achieve the high temperatures required for clean combustion. Slots in the refractory bricks provide passageways from the fuel chamber to the combustion chamber. Smaller fuel particles are prevented from falling through the slots by a fuel diversion structure (6). A variety of shapes and sizes of fuel diverter blocks are available based on the size and kind of fuel.

Once the gas is released with the gasification process, it will be drawn toward the fuel diverter and through the slots in the combustion chamber where temperatures in excess of 2000° F are attained. The powerful heat generated here spreads through the refractory lining (7) in the lower portion of the fuel chamber, evaporating water from the fuel and allowing it to gasify (pyrolysis).

In order to draw the gases into the combustion chamber, a draft-inducing fan (8) is used. The fuel can effectively burn upside down due to the negative pressure. This is important because it allows fuel to be loaded continuously without extinguishing the fire. Once the gases are drawn into the combustion chamber, they pass through the firetubes (9) where most of the heat exchange takes place. On small-scale Wood Guns like the one shown, only one firetube is present. To increase the surface area available for heat exchange in the larger models, multiple firetubes are used. After the firetubes, the gases are given a swirling action as they pass through the swirl chamber (10) and into the cyclone ash separator (11). Here, ash is removed from the exhaust air and deposited for easy disposal. Due to the unique design of both the refractory and the swirl chamber, exhaust passes through the boiler in a swirling motion that scrubs the inner chambers, preventing much of the buildup that could decrease efficiency. Exhaust air then exits through the top of the cyclone ash collector into the flue, which has cooled to about 350 F.

The Wood Gun has seals on all doors and on the automatic intake damper (air-valve). During off-cycle, the air-valve(s) closes and completely eliminate air from entering the firebox.The fire soon goes out due to lack of air. Thanks to our huge superheated refractory mass, reignition of the fire takes place immediately after off-cycle when oxygen is reintroduced to the system. By operating in this fashion we do not waste any fuel when it is not needed.

¹An assortment of fuels can be heated, such as maize, nutshells, cherry seeds, and paper pellets. Fuel sources are restricted only by nature concerns, like the number of soot produced, and fuel economy concerns, like accessibility and BTUs per pound.

Domestic Coil

This Domestic Coil shows a 100° F rise at 5 gallons per minute, 50° water inlet temperature and, 65 PSI water pressure. It is threaded into a 4 IN NPT fitting on the boiler.

Can be fixed with multiple coils as required.

Smoke Exhaust Hood

The Smoke Exhaust Hood is installed directly above the loading door and will catch any smoke that may flow out during the fuel-loading process. This smoke is then vented directly outside using its own 4-5” piping. When smoke is not tolerated, the smoke exhaust hood is necessary.

Low-Temperature Shutdown

If all the fuel has been used up in your boiler, the Low Temperature Shutdown feature stops the boiler from firing. This keeps the draft fan from blasting the residual heat out of the flue.

Cycle Timer

This feature adds a timer that allows the boiler to operate for 10 minutes per 2 hours, even if there is no call for heat. This regulates an internal temperature above the kindling point, lessening the requirement to relight the unit during times of low demand.

Oil/Propane/Natural Gas Backup

Wood Guns can be fitted with a supporting fuel option. This needs a devoted firing tube that must be constructed during production.

Automatic /Manual Switching

For #2 fuel oil, the oil backup can operate in an automatic change-over scenario, with fuel oil taking over when the boiler has ended its wood fuel. For other fuels, such as natural gas or propane, change-over is manual only.

Low Water Cutoff

A Low Water Cutoff senses the water level in the boiler’s vessel and will close the unit down if the water level falls to a dangerous level. Comes with an automatic or manual reset.

Variable Speed Induction Fan

This enables the BTU output to be effortlessly adjusted. This is done by enhancing the 1-phase motor to a 3-phase motor and steering the motor with a Variable Frequency Drive.

Automatic Feed

The Wood Gun™ series can be ordered with the capability to automatically feed itself wood particle fuels, like wood dust wood pellets, sawdust, flakes, etc. The Wood Gun™ auto-feed system inserts the fuel into the firebox from the top. You can still use logwood in the firebox with a quick change! This option comes with photo-eye sensors, which control the feed system, and an enhanced control center, which lets the user effortlessly take charge of the whole system in one location. Touchpad controls are available as well.

Additional Required Pieces:

• Rotary Airlock – Rubber blades or machined stainless steel.
• Fuel-Valve – acts as a second airlock, available in stainless steel.
• Transition Tubes – available in stainless steel – connect the boiler to Airlock, Fuel-Valve, and Auger
• Auger – available in nearly any diameter (4″, 6″, 8″, 10″) and any length
• Diverter Bricks
• Secondary Air Brick with cover

Low Pressure Steam

The Honeywell Aquastasts are changed out for Honeywell PressureTrolls and two Low Water Cutoffs are filled. An automatic water fill valve and Steam Relief-Valve are also included. In some models, the vessel is altered a little bit to let for a larger steam shelf. The Wood Gun can emit steam up to 15 psi. To know what size steam boiler you require, first, figure the amount of BTU/hr needed for your home, then add 20% to the total. This additional 20% is only required to make the initial head of steam.

Note: only available on Carbon Steel boilers.

Canister Pool Heater

Warm-up your pool with wood! Available in either Carbon Steel or Stainless Steel. This is a different canister from the vessel.

Made-to-order Engineering

At Alternate Heating Systems we have skilled fabricators and engineers ready for any design change! Whether it’s a made-to-order bin, shifting the cyclone to the other side, an additional loading door, water storage tank, or whatever you may require to fit your application.

• Gasification
• Range of Biofuels
• Fuel Efficient
• Minimal Maintenance
• Lifetime Durability
• Versatile Applications
• Automatic Feed Available
• Standard ASME Certification
• Made in USA