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Alternate Heating Systems has been making the best solid fuel boilers and hydronic heaters in the world since 1998!

2395 Little Egypt Rd, Harrisonville, Pa 17228

Most of our boilers are made to be inside, the exception being the Super E210 Outdoor Version and the Outdoor Coal Stokers. However, you can put any of our indoor boilers in a shed outside; an insulated building is recommended.

A hydronic heating system simply means a system that uses water or a water/glycol (antifreeze) mixture to carry/move the heat produced by a heating appliance throughout a home or building. The heated water is pumped from the heating appliance throughout a home or building using circulator pump. In comparison, forced air heating systems use air and a powerful blower to carry and distribute the heat produced. Forced air heating systems produce infamously dry heat and large temperature swings in your home. Whereas hydronic heating systems give a more constant room temperature and do not dry the air as forced air systems do.

All AHS boilers are closed loop systems (pressurized) NOT open or atmospheric. Our units require no water testing, additives, constant water level maintenance or external heat exchanger. A pressurized system does require a relief valve, which is included with each of our boilers, and an expansion tank.

As water heats up it expands increasing its volume and so, that extra volume needs to go somewhere. In a closed loop (pressurized) heating system there is nowhere for it to go except out of the relief valve unless an expansion tank is installed. The new expansion tanks have a rubber bladder that acts like a balloon and so give the water a place to go as it heats up. Depending on how much water is in your system will determine the size of expansion tank you need. We recommend #90 on all model producing less than 260,000BTU/hr. For larger units have a plumber perform necessary calculation to size expansion tank correctly for your system. Check out our Parts Store online.

10-15 psi is what we recommend but the relief valve will not blow off until 30 psi. All our boilers are pressure tested at 60 psi (according to ASME standards)

YES! Just install a water to air heat exchanger in the main plenum of your duct. It works very well.

Yes, we offer a domestic hot water coil as an option. It is available in our online parts store.

Anthracite is a form of clean-burning coal that is different from the more commonly known bituminous (soft) coal. It burns smoke free with very little particulate emmisions. Anthracite produces 1.63x more btu’s per pound than wood.  Its price year-by-year is very steady unlike oil and gas. It is available in Pennsylvania’s backyard.

It is by far the cheapest way to heat!

For more information click here

20 years– 10 full and 10 prorated. **The Stainless steel models’ warranty includes corrosion**

The Wood Gun began being produced in 1981. Alternate Heating Systems has been making the Wood Gun since 1998. There are still original units in use today.

Very!

1. 1. Scrape tunnels in refractory with ash rake
   2. Remove fan assembly (four nuts) clean swirl chamber, same as S130.
   3. Remove access plate on cyclone and scrape out pipe going out of the boiler.

Center bricks last from 1.5 – 2 years and the Side bricks last from 7 to 15 years

We have three options…

SS Models – any metal the fire touches is ¼” 304 Stainless steel. The outside is ¼” SA-36 Carbon steel.

SF Models – the entire firebox is is ¼” 304 Stainless steel. The outside is ¼” SA-36 Carbon steel.

CS Models – any metal the fire touches ¼” SA-36 Carbon steel. The outside is also, ¼” SA-36 Carbon steel.

We use 304 stainless steel ¼” thick, which has the best resistance to corrosion from creosote. We have been using 304 since the early 1980s and have not seen one unit corrode in all those years of service! Our vessel’s warranty on the stainless (SS) model is a whopping 20 years which includes corrosion!

Carbon steel is roughly 20% less cost than a Stainless Steel unit, but the worry of premature failure is always looming because carbon steel has no resistance to corrosion from creosote.

Side note: Hard coal does not produce creosote, so, our coal boilers, coal stokers, and coal furnaces have no need of being made from the more costly Stainless Steel.

No, the Wood Gun works great without the use of thermal storage due to its unique design and operation.

If sized correctly you will only need to add wood to the fire every 8-12hrs.

Yes! we have the option of oil, gas or propane back up. The fuel backup on the Wood Gun was tested at 85.75% efficient! The oil back up can be upgraded to allow the boiler to automatically switch to the oil burner if the wood fire were to go out. Propane and gas are manual switchover only.

Yes, as the wood in the firebox burns it emits gas (smoke). A Gasification Boiler burns the gas in a secondary burn chamber allowing them to utilize the energy that is wasted in a tradition wood boiler. Because of this you will use 65% less wood.

Third party testing confirmed an E180 Wood Gun has an overall efficiency rating of 84.6% when burning wood.

Anywhere from 24” long in the E100 up to 48” long in the E250

Only if the wood is greater than 10” in diameter.

We recommend using wood between 19-25% moisture in the Wood Gun. Stacking and covering with tarp for 1 summer will be sufficient to dry green wood to this level. However, the Wood Gun will burn wood up to 35% well if needed in emergency.

Yes, both the latch side and the hinge side of all doors are adjustable on the Wood Gun.

1. Domestic Water coil – up to 2
2. Low Temp Shutdown – fan shutdown if fire goes out
3. Cycle Timer – keeps fire alive in periods of low demand
4. Oil backup – manual or automatic switchover
5. Gas and propane back up – manual switchover
6. Outdoor rated enclosure – E155 only
7. ASME Stamp
8. Automatic Feed for particle fuels
9. Low water cutoff – safety sutdown if water level drops
10. Variable speed induction fan
11. Low pressure steam package
12. Smoke hood – 485 cfm
13. Canister pool heater – carbon or stainless steel
14. Custom engineering

When starting a cold Wood Gun (completely out of fuel) Start with a pile of kindling stacked almost up to the bottom of the load door frame. Start the kindling and allow that to burn for 30 minutes. Doing this ensures that the hot flames are being pulled down into the refractory which is key to have an efficiently burning Wood Gun. After 30 minutes you can load the boiler with enough wood to last for at most eight to ten hours. When the weather is mild the boiler should not be loaded fully or you will cause build up in the flue, heat exchanger and will also reduce overall burn times. Typically, a firebox loaded no more than 50% will last eight to nine hours in with mild weather.

If sized correctly you will only need to add wood every 8-12hrs.

6”-12” depending on which model you have. Since the Wood Gun creates its own draft, the length only has to meet the minimal safety requirements according to building codes in your area.

1. Verify you have sufficient make-up air coming into the room the boiler is in.
2. Back puffing can most always be eliminated by either changing the loading technique, changing the fuel, or both. Back puffing happens when the fuel is emitting too much gas too quickly. The following suggestions will attempt to reduce the amount of gasses being emitted.
   • The first thing we suggest would be to use higher moisture content wood.Moisture in the wood slows down the gasification process.We cannot give exact numbers as far as the moisture percentage because the percentage will differ according to the demand on the boiler.
   • Using bigger pieces are better than using all smaller pieces. Bigger pieces reduce the amount of surface area that is being subjected to the heat. With more surface area that is subjected to the heat the more gasses will be released which can cause back puffing.
3. Changing the loading technique in times of low demand.
   • The boiler should only be filled 35 to 50%.Keep in mind that 5 pieces of wood will last as long as ten pieces of wood in low demand times due to the boiler not back puffing and burning efficiently.
   • The fire box should be loaded so the fuel is stacked tightly together rather than a loose disorganized pile of wood.
4. Most of the time back puffing is caused by, overloading the boiler, fuel being too dry, restrictions in the flue and/or, overloading the boiler. Assuming you do not typically have moisture in the ash pan. In most cases moisture in the ash pan is caused by overloading with dry wood and/or a restriction in the flue. Warm and rainy days will usually reduce draft, although the wood gun creates its own draft it may be that the combination of a dreary day and possibly overloading the boiler caused your unit to condense the flue gasses and start back puffing. You would normally think that dry wood would help reduce moisture in the ash pan but, in the Wood gun it can cause it. When the fire box is full of drier wood the wood catches on fire high in the fire box. So, you end up with a huge fire throughout the fire box, but the extreme heat is not getting to the refractory. When the Wood gun burns the fire needs to be very low in the fire box so that the flames are being pulled down in the center refractory causing extremely high refractory temperatures.
5. Use the manual control damper in the back can reduce back puffing by closing it either partially or completely. Closing this damper will reduce the output of the unit but, typically it does not affect output until closed more than 60%.

1. Most of the moisture can be eliminated by either changing the loading technique, using fuel with higher moisture content, or removing any air/exhaust flow restriction (by cleaning). Your moisture is caused because you have a low stack temperature. We see this happen from time to time in low demand situations. Typically, the boiler is loaded too full for a low demand day. When the boiler is in a low demand situation the boiler should only be filled 35 to 50%. The fire box should be loaded so the fuel is stacked tightly together rather than a loose disorganized pile of wood. The issue of burning wood that is too dry can cause moisture also. The wood gun needs to build refractory temperature.

Here are a few examples of what can happen to cause this scenario.

(Example 1) When dry wood is stacked too high, the fire will not burn low in the fire box where it needs to be. It will usually build enough heat to raise water temperature but, does not raise the refractory temperature high enough for good combustion and flue temperature.

(Remedy1) Only fill the firebox ¼ to 1/3 full of dry fuel or use fuel with higher moisture content.

(Example 2) If the boiler only runs 10 to 15 minutes the refractory does not have enough time to reach a good combustion temperature.

(Remedy2) Use higher moisture content wood to slow down combustion or, raise the differential setting in the “Operate aquastat” to make the boiler run longer.

(Example 3) there may be build up or obstructions in the flue, cyclone, cyclone arm, boiler exhaust port, and heat exchanger area. A dreary or rainy day can reduce draft and may compound the problem that you already have with an obstruction.

(Remedy3) Clear any build up or obstructions in the flue, cyclone, cyclone arm, boiler exhaust port, and heat exchanger area.

2. The boiler water temperature is too low. Increase the operating limit to 175-180F

The water temperature difference between the supply and return must not be more than 20F. To fix this install a mixing valve.

1. We suggest making sure you do not have power at the socket. Most of the time the bulb just needs replaced.
2. Every once in a while, the end switch in the air valve actuator fails and stops sending voltage to the light bulb.
3. Another area to look for would be to make sure the actuator opens completely. When it is energized, it should open to where the clamp arrow on the actuator points to 90°. If it stops short, use an Allen wrench to manually crank open the actuator until it stops and then check to see if the indicator light is on.
4. If there is a continual issue with the bulb blowing it is helpful to flex the contact tab in the socket. Be sure the power to the unit is off before completing these instructions. When the bulb is out of the socket, you will be able see the metal tabs that contact the bulb. One will be solid, and one will be split so that there is a center tab that protrudes into the area that the bulb enters. Using a very small screwdriver pry up on the center tab so that it will put more pressure on the bulb.

1. How much heat demand do you have?
   • Not enough heat demand will create short “on cycles” and the refractory will not get hot enough to burn the creosote.
2. Where exactly is the creosote buildup?
   • Creosote in the firebox and air-valve is perfectly normal and should be expected.
   • Creosote beyond the refractory (i.e., fire-tube, heat exchanger, cyclone, flue) should not happen on a properly loaded/run, and well-maintained Wood Gun.
3. Are the doors and gaskets sealed well?
   • An improper/old/loose seal on the load door and the air valve disc will allow an enough oxygen in to the firebox to sustain a smoldering fire causing creosote
   • An indicator of a bad load door seal is creosote leaking out around it.
4. How full do you fill the fire box?
   • Do not overfill the firebox so that the burn times extend past 12hrs.
5. How long does the boiler last and still relight?
   • If not more than 1hr then the refractory is not getting hot enough. Either you do not have enough heat load, or the Boiler/flue need to be cleaned.
6. How long will one load last?
   • If over 12hrs decrease the amount of wood used when loading
7. How long has it been since it was cleaned out?
   • Dirty boiler/flue restricts airflow causing smoldering fires.
8. How long does the on cycle last?
   • If not more than 1.5hr at first (cold) start or >20min on cycles thereafter, then the refractory is not getting hot enough. You do not have enough heat load.
9. What diameter are the logs?
   • If all the logs loaded are 9” or more the boiler will be more susceptible to a smoldering fire, allowing creosote to form. Try mixing in the larger rounds with some smaller rounds.
10. What is the stack temperature?
    • The Stack temperature will be 250F – 375F on a clean boiler that is running well, if less than 250F then that indicates a smoldering fire.
11. How tall is the stack?
    • To tall of a stack will cause the gases to cool and condense before they exit the stack.
12. Was the cyclone removed from the boiler and cleaned?
    • An important but often missed part in the annual cleaning of the boiler.
13. Check that your center plug is installed and is in good condition.
14. Check the refractory tunnels and rear door (if equipped) and clean them of all ash.

1. Control malfunction. Please call for troubleshooting.
2. Incorrect control setting.
   • High Limit factory set to 200F; Operate Limit factory set to 180F.
3. Intake air-valve disc or load door not sealing properly.
   • Clean if coated with creosote, replace if worn.
   • The load door may need adjusted tighter.
4. Excessive chimney draft.
   • Greater than -.08inWC measured when boiler is hot and draft fan is off. If greater than -.08inWC install/adjust barometric damper.

1. How much heat demand do you have?
   • Not enough heat demand will create short “on cycles” and the refractory will not get hot enough to burn the creosote and smoke.
2. How full do you fill the fire box?
   • Do not overfill the firebox so that the burn times extend past 12hrs.
3. How long does the boiler last and still relight?
   • If not more than 1hr then the refractory is not getting hot enough. Either you do not have enough heat load, or the Boiler/flue need to be cleaned.
4. How long will one load last?
   • If over 12hrs decrease the amount of wood used when loading
5. How long has it been since it was cleaned out?
   • Dirty boiler/flue restricts airflow causing smoldering fires.
6. How long does the on cycle last?
   • If not more than 1.5hr at first (cold) start or >20min on cycles thereafter, then the refractory is not getting hot enough. You do not have enough heat load.
7. What diameter are the logs?
   • If all the logs loaded are 9” or more the boiler will be more susceptible to a smoldering fire, allowing creosote to form. Try mixing in the larger rounds with some smaller rounds.
8. What is the stack temperature?
   • The Stack temperature will be 250F – 375F on a clean boiler that is running well, if less than 250F then that indicates a smoldering fire.
9. Was the cyclone removed from the boiler and cleaned?
   • An important but often missed part in the annual cleaning of the boiler.
10. What is the moisture level of the wood being burned?
    • You would normally think that dry wood would help reduce smoke but, in the Wood Gun it can cause it. When the fire box is full of drier wood the wood catches on fire high in the fire box. So, you end up with a huge fire throughout the fire box, but the extreme heat is not getting to the refractory. When the Wood Gun burns the fire needs to be very low in the fire box so that the flames are being pulled down in the center refractory causing extremely high refractory temperatures.
11. Check that your center plug is installed and is in good condition.
12. Check the refractory tunnels and rear door (if equipped) and clean them of all ash.

1. Check the pressure in the system if less than 30psi the relief valve is faulty, please replace.
2. You may not have a large enough expansion tank. Water expands and contracts as it heats and cools. We recommend #90 on all model producing less than 260,000BTU/hr. For larger units have a plumber perform necessary calculation to size expansion tank correctly for your system.
3. Your domestic coil may be leaking. Replace or isolate the domestic coil.

• 20 years- 10 full and 10 prorated on the vessel
• **The grate is Lifetime Warranty**

NO, because anthracite coal inherently burns very clean and smoke free, the Coal Guns will not produce any smoke. Anthracite coal does not produce creosote when burned! Making Anthracite clean, neighborhood friendly, and very safe to burn.

The Coal Gun burn “pea” or “buckwheat” size Anthracite (Hard) coal.

No, The Coal Gun adjusts the feed rate automatically, thanks to our signature Thermal Ash Monitoring System.

Only 1x per per year!

1. Remove fan assembly (four nuts) clean swirl chamber with a scraper and vacuum.
2. Remove flue tube weldment on top of boiler and scrape/vacuum out pipe going out of the boiler. Including the square hole on side of pipe, and the funnel at the bottom.
3. Bolt everything back together!

The indoor Coal Gun’s hopper hold roughly 350 LBS. These can also be fitted with an auger to automatically feed coal into the hopper.

The Outdoor Coal Gun’s have a much larger hopper holding 2,000 and 3,500 pounds on the S130 OBE and the S260 OBE, respectively.

Roughly 1 full hopper of coal = 1 pan of ash.

New for 2020, the S130 & S260 indoor modes have the ability to have an oil, gas, or propane backup.

The S500 & S1000 do not have that ability.

Yes, if you purchase the outdoor Coal Gun. The S130 OBE comes with a 2000lbs hopper or the S260 OBE comes with a 3500lbs hopper.

1. The coal was wet when loaded in the hopper.
2. If the coal was dry, then, the fire is getting too close to the neck of the hopper.
   • Raise the temp setting on the thermal ash sensor
   • Increase the fan speed if equipped with belt drive.

1. Excessive chimney draft. Greater than -.08inWC measured when boiler is hot and draft fan is off. If greater than -.08inWC install barometric damper.
2. Sight tube draft flap not releasing when draft fan is off.
   • Check spring for proper tension.
   • Excessive chimney draft
3. Aquastats set too high or malfunctioning.
   • High Limit factory set to 200F, Operate Limit factory set to 180F

1. Are you starting your Coal Gun correctly
   • When starting your Coal Gun be sure you turn the grate “off” until the thermal ash sensor is reading higher than its set temp (factory set to 130F). It may take up to 10hrs.
   • When starting your Coal Gun be sure you have enough heat demand so that the boiler does not shut down for at least 3hrs so that the fire becomes fully established in the coal pot.
2. You do not have enough heat demand.
3. Try using Pea sized Anthracite Coal.
4. What is the Thermal Ash Sensor set to?
   • Factory set to 130F.
   • It should not typically be set below 110F.
5. You may have large clinkers.
   • Clinkers are chunks of coal ash that have been fused together by the high temperatures. Some coal is more susceptible than others.
   • To remove large clinkers, remove the draft cover, and move draft flap to the side. Be sure to wear gloves to provide protection against burns. Insert a metal rod in the sight tube and run it up and down (to the grate) through different areas of the coal pile checking for clinkers.
   • Use the rod to break up any clinkers you find. If necessary, you can use a hammer to strike the end of the rod to break them up. You will not damage the grate if you hit it as it is made of 1/2” steel. Once the clinkers are broken up, they will fall on to the grate and be carried to the ash pan.
6. Is your chimney producing enough draft?
   • First check the draft in your stack. If lower than -.04inWC the first thing we recommend is eliminating the barometric damper if installed. The best way to increase draft is to add length to the chimney, or a draft inducer may be used which will also require a barometric damper.
   • If you are only losing fire in the warmer months, when the draft will drop to its lowest point, it may be too low for the boiler to maintain a fire. Because in the colder months, the flue will be warmer due to the boiler running more often and the temperature difference between the outside and the inside of the house will be greater causing you to have more draft.
7. If your chimney is producing enough draft, it is time to completely clean your Coal Gun.

1. Verify you have sufficient make-up air coming into the room the boiler is in.
2. Make sure you are burning Pea or Buckwheat size anthracite coal.
   • If you are burning Buckwheat and are still having issues, try Pea sized anthracite coal.
3. Your chimney draft cannot be less than -.04inWC.
   • Measure the draft in the flue when the boiler is hot, and the draft fan is off.
4. You may have a blockage in the system. Shut the unit down and clean it thoroughly.
5. The fire may be burning too low the coal pot. After the draft motor has been on for >15min look in the sight tube and verify the fire level in the coal pot. You should see 25-50% unburnt coal and 50-75% burning coal.
   • If you see more than 50% unburnt coal in the sight tube. First, make sure you had the grate “off” when you first started the fire. Then, decrease the Thermal Ash Sensor temp setting by 5deg. Wait 1 day then check the fire level again. If problem persists you may continue decreasing by 5deg interval waiting 1 day in between. Do not go less than 110F.
   • You may also need to adjust the Grate Timer. Please call us, we would be happy to assist you.

1. Coal is 10% ash so when coal is burnt perfectly the ash should be 10% of what was added. Divide the amount of ash measured by the amount burnt and then multiply that by 100. Keep in mind no coal boiler is able to burn coal perfectly but under 18% is very good.
2. • This should be measured every day, five days in a row, and measure it at the same time each day.
   • If 7lbs of ash was measured and 50lbs of coal was loaded into the hopper. It would be 14% percent unburned coal. 7/50=.14
3. Is the Grate Switch in Mode 1 or Mode 2?
   • Try running the boiler in Mode 2.
   • If you have no Mode 2, give us a call.
4. When was the boiler started?
   • May just be residual from start-up.
   • May not have left the grate off long enough.
5. What is the ambient temperature of the room?
   • If in an out-building or anywhere the boiler may be able to pull in cold outside air directly may need the ash temp set lower than average. Give us a call!
6. What is the Grate temperature set at?
   • May need to set the temp lower. Decrease the Thermal Ash Sensor temp setting by 5deg. Wait 1 day then check the fire level again. If problem persists you may continue decreasing by 5deg interval waiting 1 day in between. Do not go less than 110F.
7. You may also need to adjust the Grate Timer. Please call us, we would be happy to assist you.