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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

What is Afterburner Technology?

Afterburner Technology allows you burn 40% less wood and have 90% fewer emissions than traditional legacy furnaces. That means you save even more and enjoy cleaner air at the same time!
Learn more about Afterburner Technology here.

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Do I have to buy an Afterburner 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.

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Can I heat another building?

These models are designed to heat two or more buildings:

  • HE2100
  • GX30
The following models are designed to heat a single building:
  • HE1100
  • GX10
  • GX15
With these models, extra equipment may be required to heat another building.

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.

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Is it better to have a Stainless Steel outdoor furnace?

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.

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How much does a Hawken furnace weigh?

Learn about the various Hawken Furnace models here

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Can I save money by taking delivery at the Hawken factory?

You may, because you save the cost of freight.

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Can I burn coal in a Hawken furnace?

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.

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Are coal-burning furnaces exempt from EPA regulations?

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.

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Where can I buy hawken Energy Outdoor Wood Furnace?

You can buy Hawken Energy Furnaces to closest Authorized Dealer in your location, or you can contact us at +1 (231) 861-8200.

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Why would I choose to purchase Hawken Energy Furnace?

Compare Hawken Energy Furnace from other outdoor wood furnace manufacturer by checking out this page Comparison Tool

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Why a Hot Water Kit?

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.

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Can I take advantage of Financing?

Yes,we offer financing to our customers.
Take advantage of Hawken Energy Financing

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Installation

Should I have a Water Softener?

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.

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What Pipe is Best for an Outdoor Wood Furnace: Pex vs. Pex-al-pex.

The basic pex pipe is cross-linked polyethylene. Pex is widely accepted in and available at most home centers. It's a great option for domestic water installations. Learn more

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What are the steps to installing a furnace?

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)

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I hear PEX & PAP, what is the difference?

We work with both types.

  • PEX (or crosslinked polyethylene) is part of a water supply piping system that has several advantages over metal pipe (copper, iron, lead) or rigid plastic pipe (PVC, CPVC, ABS) systems.
  • The PAP (PEX-AL-PEX) composite capitalizes on the corrosion and chemical resistance of plastic and the pressure capacity of metal by laminating the aluminum layer between layers of plastic. The resulting tubing is non-corroding, bendable for form stability, flexible, and resists most acids, salt solutions, alkalis, fats, and oils.
    • Learn more about how they are compared.

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      Is it a good idea to have stack extensions?

      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.

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      What is an in house fill?

      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.

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      Can I connect a Hawken to an indoor boiler? or any other heating system?

      Most dfinitely! A Hawken furnace can be connected to 99 percent of homes in the US.

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      How do I determine which unit heater to use?

      This is determined by the area and heighth of the celing as well as the quality of the insulation in the building of space you are heating.

        For Hawken furnace technical details. Click on Select

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        I am doing my own install to save money, will you help me?

        Yes, have guides for self installers

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        Should my stove be level?

        Yes, this helps with the proper flow of the water in the water jacket and through the pump.

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        How far from my house must the furnace be?

        30 to 50 feet from other structions, 10 feet clearance from combustibles, follow insurance/local ordinance guidelines

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        Can I install underground and inhouse pipe and exchangers before I receive my furnace?

        Yes, but must remember an open 12 " square by rear of furnace.

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        Can I install my Hawken Energy Outdoor Wood Furnace by myself?

        There are 3 options to install Hawken Energy Furnace

        • Certified Hawken Energy Installer
          • Contractor you know that has technical background regarding basic wiring and furnace installation
            • Yourself with Hawken Installation Guide. Installation Procedure Using (PEX Pipe or PAP Pipe)

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            • Can I heat my house without duct work?

              Yes, Radiator system, radiant in floor system, Unit heater

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              May I use a forklift to move my furnace?

              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.

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              Choosing the Right Underground Pipe for Your Outdoor Wood Furnace

              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 2

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              I want radiant heating system what do I do?

              Contact a company for a system.

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              Do I need a concrete pad for my new Hawken?

              No, but you need leveled fire brick or concrete under the feet of the furnace.

                For proper fire brick placement See Diagram

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                What is a Unit Heater?

                These heaters consist of a blower fan and a heat exchanger and they are controlled by a thermostat so you can control the heat.

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                Where should I place my unit heater?

                Our units can be attached to the ceiling.

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                What does forced air mean?

                It is a heating system the uses a blower to force the heat thru a system of ductwork.

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                Finding the Best Location for your Outdoor Wood Furnace

                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

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                How deep should underground piping be?

                24 inches- 30 inches

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                How do I put my pump in?

                Close the isolation value, remove pump, insert new pump ensuring that the pump shaft is parallel to the ground.

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                What is the use of a Thermostat?

                A device that automatically regulates temperature, or that activates a device when the temperature reaches a certain point. How it is installed? Learn more

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                Do I lose water temperature in the underground piping?

                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.

                Although outdoor prevailing wind and smoke considerations should be given first priority, your outdoor furnace location selection may also minimize the amount of purchased pipe required. Authorized Hawken underground pipe loses very little heat, so longer distances will not cause significant heat loss, but reducing distance will reduce cost of purchased pipe. Finally, keep in mind that the underground pipe must enter the home or building to be heated, and plan for this accordingly"

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                Operating a Furnace

                Why is it important to keep the furnace full of water?

                If you don'tuse seasoned wood, You will burn more wood, the furnace wil be less efficient, and it can damage the metal.

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                Do I have to turn my water heater off in the winter Time?

                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.

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                How can I identify if Hawken Furnace fan is defective?

                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.

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                What does the damper do?

                1. Opens the draft so the smoke exits the firebox when you are filling the furnace.

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                Should I use Antifreeze in my furnace?

                You may use antifreeze, you would follow the recommendations of the manufacturer for the ratio. Antifreeze reduces the efficiency

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                Do I have to worry about my outdoor wood furnace system freezing?

                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.

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                Can I burn green wood?

                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 furnace

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                If I don't use chemicals in the furnace water, what happens?

                The water treatment coats the inside of your system and helps to slow down the development of rust and corrosion in your system.

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                Am I burning too much wood?

                You may be. Is the wood properly seasoned? Have you cleared the firebox?

                High wood consumption can be caused by a number of factors. Learn more

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                What is the disadvantage if I will not use a water softener?

                Furnace efficiency, and would clean the in house filter less often.

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                Why do I need a water filter?

                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.

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                Can I burn coal in my Hawken?

                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.

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                What does the water treatment chemical do?

                The chemical coats the inside of the furnace to reduce the effects of corrosion on the metal.

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                Why shouldn't I fill my furnace with wood?

                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.

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                Can I leave my furnace over the weekend?

                You may have someone "feed" your furnace for you or you may lower the thermostat temperature

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                How do I keep mice out of my furnace?

                Caulk around where the underground comes in the bottom of the furnace.

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                Can I adjust my furnace operating temperature?

                The furnace operates at 160 to 180 degrees.

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                How do I set up to leave my furnace off for a month in the winter?

                Follow shut down procedurs in your manual. You may chose to keep the pump circulating.

                Hawken Shut Down Procedures
                Please observe the following steps when shutting down the furnace:
                1. Observe all safety precautions
                2. Allow time for the fire and coals to completely burn out.
                3. Empty all the ashes and lightly scrape out the firebox to remove all ashes.
                4. Fill the system with water until it is completely full.
                5. Flush and clean the filter.
                6. Make sure the proper water treatment procedure is followed
                7. Make sure the chimney cap is in place to prevent rainwater from entering firebox.
                8. 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.

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                What do I do when I go away for a month?

                Follow shut down procedures, unless you have someone to keep furnace going.

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                Should I turn my thermostat down at night?

                No, the lower the water temperature will cause the use of more wood to recover .

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                What do I do after I shut down my furnace after heating season?

                Follow shut down procedurs in your manual. You may chose to keep the pump circulating.

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                Do I have to drain my furnace if I'm away for a long time?

                no, as long as you have filled the furnace, added the proper amount of water treatment & keep the pump circulating the water

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                Why should I use seasoned wood?

                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.

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                What are the critical items to operate and maintain my furnace efficiently?

                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 regularly

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                Is it a disadvantage to drain my furnace?

                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.

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                Maintenance

                What is the Importance of Catalyst in my GX Series Furnace?

                Without or a damaged catalyst in place, furnace will produce more fine particulate emissions and may run less efficiently.

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                Emergency Parts to Keep on Hand for your Hawken Energy Outdoor Furnace

                There are only a few components on a Hawken furnace that could go bad and be hard to find a replacement for quickly. These are

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                How do i often clean the Afterburner Furnace?

                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 140F.

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                Inspecting GX Series Catalyst

                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.

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                How do I Clean the Lower Ash Chamber?

                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 container

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                Afterburner Routine Cleaning

                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.

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                Why do I have to replace my brush each year?

                What to Inspect & How to Clean Filter (inside house/building)

                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.

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                What do you mean by proper ash management?

                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.

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                Why do I need to Check Water Level/Fill?

                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.

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                Why is ash management important?

                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.

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                How Important is the Door Rope/Seal?

                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.

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                Why is water treament important?

                The chemical (water treatment) coats the inside of the furnace to reduce the effects of corrosion on the metal.

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                How often do I need to Inspect my Chimney/Flue

                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.

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                Do I need to replace the firebrick in my GX Series?

                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."

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                How Can I Change Door Rope Gasket

                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 more

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                Parts

                Hawken Energy Unit Heater Specs.

                See Unit Heater Specs here

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                How do I order parts?

                You may contact your local dealer, you may use the online store or you may order directly from us.

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                May I buy parts directly from Hawken?

                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.

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                How can I learn part prices?

                Same choices, local dealer, online store or direct from us.

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                What is the purpose of THERMOSTATIC LOAD VALVE (TLV)?

                A thermostatic bypass valve may be installed in the system to prevent the water in the furnace from getting too cool.

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                What is Solenoid?

                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.

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                Troubleshooting

                Why does smoke come out through my door?

                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.

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                My pull rod separated; what do I do?

                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.

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                What is the difference between white smoke & black smoke?

                Black smoke is unburned carbon

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                My door frame appeared to be warped. Do I need a new door?

                Check to see if door is just out of adjustment, Check door gasket.

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                All fittings are leaking?

                Have you cleaned your filter recently? Tighten the fittings

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                My furnace stopped running what should I do?

                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?

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                My Furnace is leaking, What do I do?

                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.

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                Why am I not getting hot water?

                Check that the hot water system is connected properly. Check if the heat exchanger is partially or totally clogged.

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                How do I replace my HE Series blower?

                See the link below for detailed instruction on how to replace both the solenoid and the blower. Keep in mind it is not always necessary to replace both components at the same time. Use gloves and safety glasses. Learn more.

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                Why does my furnace continue to burn when it is not operating?

                Check the door seal, door adjustment, and soleinoid.

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                I have Electrical Problems?

                Use this Electrical Troubleshooting Flow Chart. Learn more.

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                I can't find a leak in my furnace. Why am I losing water?

                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.

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                What are the Common Pex Pipe Problems

                Pex has its problems, however, and those should be understood when considering the piping. Learn more.

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                My pull doesn't pull. Why?

                There may be soot built up around the damper. You will need to clean from the chimney side

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                Still need answers?

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