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Frequently Asked Questions
We have compiled many of the most frequently asked questions. You can look through these questions and also browse our knowledgebase for help.
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Purchasing a Furnace
As of January 1, 2016, the EPA requires all furnaces sold to residential customers pass an emissions standard. Afterburner furnaces are EPA approved and have the best emission ratings in America. Commerical or business customers are not affected by the regulation.Show Less ▲
These models are designed to heat two or more buildings:
Even though all of our furnace models can be configured to heat multiple buildings, always use a furnace that is large enough for your needs. Operating a furnace that is too small will require more frequent loading of wood fuel, and during the coldest days, may not provide enough heat. Learn more. Show Less ▲
Not necessarily. Stainless steel has many favorable qualities, but stainless steel furnaces are more expensive and require more fuel for the same amount of heat. We have found that with proper maintenance and water treatment, structural carbon steel is just as reliable and can save you a lot more money.
Please see our compare page for more information.
You may, because you save the cost of freight.Show Less ▲
Burning coal can damage your Hawken furnace and will void your warranty. Because coal burns hotter than wood, burning coal in a legacy furnace can damage the bottom of the firebox. Burning coal in an Afterburner furnace will ruin the catalyst resulting in reduced operation or failure of the furnace.Show Less ▲
The new EPA regulations state that coal burning furnaces are exempt from the new emission standards. However, manufacturers of coal furnaces cannot use "wood-burning" in any of their advertising or warranties.
Put another way, it is against the law for a manufacturer to provide a warranty for a coal burner that burns wood unless that furnace passes the emission standards.
Please see EPA regulations regarding coal burning furnaces for more information.
One of the great things about a Hawken Energy outdoor wood furnace is the versatility of the heating options. Hot water circulated from the Hawken can be used to heat forced air systems, boilers, garages, shop space, pools and hot tubs, green houses and all kinds of other utilities. We've even seen wood drying kilns utilize the abundant heat of a Hawken Energy system.Show Less ▲
You can if there is a leak in the UG, You should also seal the ends of the UG with foam insulation to the system air tight.The unual heat loss is one degree in our systems if they are installed properly.
Close the isolation value, remove pump, insert new pump ensuring that the pump shaft is parallel to the ground.Show Less ▲
Outdoor furnace installation involves the following TEN basic steps: 1. Underground pipe installation 2. Furnace placement 3. Back of furnace electrical wiring 4. Back of furnace primary line hookup 5. Back of furnace second line hookup (optional) 6. Indoor filter system 7. Indoor fill kit 8. Hot water system interface (optional) 9. Indoor heating system interface 10. Additional line heating system interface (optional)Show Less ▲
We work with both types.
By having a water softner you are able to reduce the builder up of minerals in the heat exchangers in your system. If you have really hard water you can clog these in several months.Show Less ▲
When the top of you chimney is lower than the peak of your neighbors roof, you will need chimney extensions. Ensure the extension are insulated chimney extensions.Show Less ▲
It is a hook up in the house that allows the owner to fill the furnace from the house without having to add water to the furnace in the snow, rain, etc.Show Less ▲
Most dfinitely! A Hawken furnace can be connected to 99 percent of homes in the US.Show Less ▲
30 to 50 feet from other structions, 10 feet clearance from combustibles, follow insurance/local ordinance guidelinesShow Less ▲
Yes, have guides for self installersShow Less ▲
Yes, this helps with the proper flow of the water in the water jacket and through the pump.Show Less ▲
Yes, Radiator system, radiant in floor system, Unit heaterShow Less ▲
Yes, but must remember an open 12 " square by rear of furnace.Show Less ▲
The GX- 10 has loops to move by forklift, HE 1100 & HE-2100 need to have fork extensions to move with forklift. Or you may use the eye with a safety strap.Show Less ▲
There are lots of options available when it comes to installing the underground pipe for your outdoor wood furnace. Sectional or seamless, foam or foil wrapped, the right underground piping can make a huge difference in how effective your outdoor wood furnace operates. Read more 1 Read more 2Show Less ▲
These heaters consist of a blower fan and a heat exchanger and they are controlled by a thermostat so you can control the heat.Show Less ▲
It is a heating system the uses a blower to force the heat thru a system of ductwork.Show Less ▲
Operating a Furnace
1. Keep water full 2. Manage ash 3. Use water treatment 4. Use season wood 5. Keep fire in the middle of firebox 6. Clean tubes regularlyShow Less ▲
In order to ensure that there is no chance of water freezing you need to blow the lines clear of water if the system is drained.Show Less ▲
The better the wood is seasoned the less moisure content it has. The higher the moisure content the lower the amount of BTU available for heat. You will use more wood, need to fill the furnace more often and have to clean the furnace more frequently.Show Less ▲
No, There is no strain on the system to heat both your home and your water as long as you purchased the correct size of furnace for the area you are heating.Show Less ▲
This can be evaluated by simply observing the fan and feeling airflow. Also, the solenoid that lifts the damper plate can fail (sometimes if there is an electrical short in your home somewhere, this will manifest). Test this by turning on the blower fan switch (located inside the control box) and you should hear a click. Turn it off and hear a similar sound. If not, open the blower box to inspect.Show Less ▲
If you don'tuse seasoned wood, You will burn more wood, the furnace wil be less efficient, and it can damage the metal.Show Less ▲
You may use antifreeze, you would follow the recommendations of the manufacturer for the ratio. Antifreeze reduces the efficiencyShow Less ▲
No. With 180 degree water, the system will never freeze as long as the outdoor furnace is running and the pump is working. Even without wood, the furnace will absorb some heat from the indoor loop further preventing freezing. The outdoor furnace is highly insulated which minimizes heat loss, even in the coldest weather.Show Less ▲
1. Opens the draft so the smoke exits the firebox when you are filling the furnace.Show Less ▲
Furnace efficiency, and would clean the in house filter less often.Show Less ▲
Green wood has more moisture than seasoned wood. The more moisure in the wood the more water the furnace must work to eliminate. The water accumulates on the walls of the furnace which allow creosote to build up quickly in the furnaceShow Less ▲
The water treatment coats the inside of your system and helps to slow down the development of rust and corrosion in your system.Show Less ▲
The chemical coats the inside of the furnace to reduce the effects of corrosion on the metal.Show Less ▲
The water filter removes particulates from the water. These can build up in the heat exchangers, causing them to work less effectively, & can clog the exchangers.
Water cleanliness is important to reduce erosion within your water system. Debris such as dirt or rust particles should be filter or flushed from the water system.Show Less ▲
Just as you wouldn't fill your gasoline powered vehicle with diesal fuel, you should not burn a fuel that is not recommended for your Hawken furnace. Burning coal can damage your furnace and will void your warranty. Because coal burns hotter than wood, burning coal in a legacy furnace can damage the bottom of the firebox. Burning coal in an Afterburner furnace will ruin the catalyst resulting in reduced operation or failure.Show Less ▲
Caulk around where the underground comes in the bottom of the furnace.Show Less ▲
The furnace should not be filled to more than 2/3 capacity and the fire should be 8" from the mouth of the firebox. If the fire is too close to the mouth of the firebox, it can damage or warp the door. If the fire is too high in the firebox, it can weken the metal from excessive heat.Show Less ▲
You may have someone "feed" your furnace for you or you may lower the thermostat temperatureShow Less ▲
Follow shut down procedures, unless you have someone to keep furnace going.Show Less ▲
The furnace operates at 160 to 180 degrees.Show Less ▲
Follow shut down procedurs in your manual. You may chose to keep the pump circulating.
- Observe all safety precautions
- Allow time for the fire and coals to completely burn out.
- Empty all the ashes and lightly scrape out the firebox to remove all ashes.
- Fill the system with water until it is completely full.
- Flush and clean the filter.
- Make sure the proper water treatment procedure is followed
- Make sure the chimney cap is in place to prevent rainwater from entering firebox.
- If you have a forced air furnace with a second thermostat controlling your indoor furnace blower fan, be sure to turn off the power to this thermostat.
Follow shut down procedurs in your manual. You may chose to keep the pump circulating.Show Less ▲
no, as long as you have filled the furnace, added the proper amount of water treatment & keep the pump circulating the waterShow Less ▲
No, the lower the water temperature will cause the use of more wood to recover .Show Less ▲
Check for normal wear and tear. Ensure all air flow holes in brick are not altered. Visually inspect the lower burn chamber to make sure all the brick are standing vertically, not tilted or out of place. Replace any firebrick as necessary. Insulation and firebrick are not covered by the warranty. New brick may be obtained by contacting Hawken Energy.
NOTE: The Hawken Energy GX series Afterburner utilize firebrick refractory to contain the high temperature burn of the combustion process."Show Less ▲
The rope will settle in the first few months of use. Before you change the rope gasket try adjusting your door. This is easiest with two people, one to push the door against the chute and the other to adjust the bolts. Keep your door snug but not so tight that it is difficult to operate. Learn moreShow Less ▲
Without or a damaged catalyst in place, furnace will produce more fine particulate emissions and may run less efficiently.Show Less ▲
Furnace must be cleaned every two weeks. Regardless of how dry and seasoned your wood is. if ANY cleaning step is missed, the tubes will get clogged and you will also not get proper combustion. This will lead to the Afterburner operating below 140°F.Show Less ▲
While cleaning the heat exchange area check the catalytic disk. Make sure the catalyst is well seated and clean. Though not required for proper operation it is recommended that the catalyst be kept in place during normal operation. Replace the catalyst every five years for maximum catalytic efficiency.Show Less ▲
Use caution. Only open the lower back door when furnace is switched to off position. Using the provided cleaning/scraping tool, remove ash from lower chamber as necessary, at least every week. Always remove ash into a covered, non-combustible containerShow Less ▲
The GX Series Afterburner must be cleaned regularly; at least twice per month during the heating season and/or year-round use. Once every two weeks, the heat exchange tubes must be cleaned. This process should take no more than 15-20 minutes as part of regular maintenance.
NOTE: Check daily for creosote buildup until experience shows how often cleaning is necessary. The hotter the fire the less creosote is deposited. Cleaning may be required more often when the weather is milder and less often when the weather is colder.Show Less ▲
Inspect filter for any sediment. When necessary, flush filter by opening the Filter By-Pass valve and close the valves on both sides of the visible flow filter. This allows the system to continue to circulate while you discharge the filter of all collected materials. Open the ball valve on the clean water side of the filter. Then, while holding a bucket under the filter, open the valve at the bottom of the filter to flush out the stainless steel filter, close that valve again once clear. This method generally cleans the filter without disassembly. Open both filter valves and close the by-pass valve. This should be done once a month.
For detailed process Check this Video.Show Less ▲
The manner in which you correctly remove and position the ash in the firebox.
Remove ash and coals every week and scrape firebox clean. Never operate the furnace with a fire in it with the door open, except for brief periods while loading wood or removing ash. Always remove ash into a covered, non- ombustible container. Clean ash from all firebox surfaces, especially the rear plate and side plates.DO NOT ALLOW ASH TO BUILD UP ON THE STEEL SURFACES.Show Less ▲
Always keep the Afterburner full of water. On a daily basis, check the water level indicator located in the vent tube at the peak of the roof towards the front of the furnace. If not full, open in-house fill valve until full. Normally, this step should be taken once a month by opening the in-house fill valve for a few seconds until water spills out on the roof of the furnace. Add water to furnace slowly.Show Less ▲
If the ash becomes wet it is corrosive to the metal of the furnace. If the level of ash is too thick in the waterbox it does not allow for efficient heat transfer to the water in the water acket of the furnace. The temperature of the water in the jacket is used to heat your house.Show Less ▲
Inspect door seal fire rope monthly or as needed. Make sure door seals properly to prevent air from entering furnace; this will cause the furnace to overheat and can cause serious damage to the furnace. If necessary, replace fire rope. If necessary, adjust door for proper fit. Never operate the furnace with a fire in it with the door open, except for brief periods while loading wood or removing ash. When replacing fire rope or adjusting door for proper seal, be sure to remove any fuel from furnace to prevent overheating, since door may be open for more than a few minutes.Show Less ▲
The chemical (water treatment) coats the inside of the furnace to reduce the effects of corrosion on the metal.Show Less ▲
Inspect chimney and flue monthly and clean as needed. Clean chimney and flue annually. Perform cleaning and maintenance only when no fire is present in the firebox and ashes are cooled completely.Show Less ▲
is a type of electromagnet when the purpose is to generate a controlled magnetic field. If the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.Show Less ▲
You may contact your local dealer, you may use the online store or you may order directly from us.Show Less ▲
Yes, but you will have to pay the shipping costs from Michigan to your location. Your local dealer will usually offer the best deal for both parts and furnaces.Show Less ▲
Same choices, local dealer, online store or direct from us.Show Less ▲
A thermostatic bypass valve may be installed in the system to prevent the water in the furnace from getting too cool.Show Less ▲
There may be soot built up around the damper. You will need to clean from the chimney sideShow Less ▲
There are several adjustments that you can make to the door. Your door seal may be worn and need replacement. The seal usually needs to be replaced about every 3-5 years. It may be sooner if the wood is too close to the door in the fire box.Show Less ▲
Black smoke is unburned carbonShow Less ▲
There is a nut & bolt that holds the D plate on. You can look through the chimney to see if see if the nut and bolt are still present. You may also look through a hole in the back of the firebox to see if it is there.Show Less ▲
Check to see if door is just out of adjustment, Check door gasket.Show Less ▲
Inspect the thermometer well, the aquastat well, the drain plug, the factory mounted feed plug and the return cap, as well as any other fittings added in the field for leaks. Loose fittings are the most common cause of Leaky furnaces.Show Less ▲
Check if there is there power to the furnace? Does the light work? Check the high limit switch? Is the blower and or solenoid working? Are the wires in good condition?Show Less ▲
Check that the hot water system is connected properly. Check if the heat exchanger is partially or totally clogged.Show Less ▲
Check the door seal, door adjustment, and soleinoid.Show Less ▲
The furnaces uses a non-pressurized system, this means that the system is exposed to the air. Since the water in the system can and will be warmer than the air, there will be evaporaration of the water in the system.The water must be check and adjust at least once a month, sometimes more.Show Less ▲