Wood furnaces run on a simple principle: take the heat from burning wood and use it to warm your home. The processes by which they accomplish that goal, though, are complex. Many systems must work together seamlessly to deliver heat efficiently and vent out combustion byproducts safely, all while meeting proper emissions standards.
At HY-C, we manufacture wood furnaces under our Fire Chief and Shelter brand names. Two models — the Fire Chief FC1000E and the Shelter SF1000E — have been installed in thousands of homes across the world.
At the same time, our customer service team has assisted with plenty of installation questions, electrical glitches, and heating queries involving these two furnaces. We’ve taken the most common questions that come up about the units, and we’re going to discuss them here.
So if you own a Fire Chief or Shelter furnace and you’re experiencing problems with your distribution blower, dealing with a continuously running draft blower, or your home just isn’t heating up the way you want it to, we're here to help.
Note: The Fire Chief FC1000E and Shelter SF1000E operate similarly and feature similar components. For troubleshooting purposes, both furnaces may be viewed interchangeably.
Table of contents (click to jump to a question)
- Thermostat installation
- Firebrick layout
- Odor during initial firing
- Flames emitting from furnace door during reloading
- Distribution blower problems
- Draft induction blower problems
- Excessive smoke during reloading
- Home isn’t heating up
- Downdraft on chimney
- Furnace door won’t seal
- Creosote buildup in chimney
Fire Chief and Shelter Furnace Components
Before we get going, let’s cover the major parts that control the operation of these furnaces (just so we’re on the same page). There are three components to pay attention to:
- Draft blower: This small fan blows air directly into the firebox to make the fire burn hotter
- Distribution blower: This large fan blows hot air from the furnace into the ductwork to spread heat into the home
- Fan limit control: This box controls the point at which the distribution blower turns on and off. It also controls when the draft blower turns off.
Of all the questions we get about our furnaces, homeowners undoubtedly inquire about the fan limit control more than any other part. Since that’s the case, it’s worth taking a little detour to discuss this small yet vital furnace component in more depth.
Fan Limit Control
As its name implies, the fan limit control controls both of the fans (the distribution blower and draft blower) on the FC1000E and SF1000E. On the silver-colored dial, there are three adjustable point indicators that control what the furnaces’ fans do:
- The leftmost point indicator tells the distribution blower to turn off (at 100 °F)
- The middle point indicator tells the distribution blower to turn on (at 150 °F)
- The rightmost point indicator tells the draft induction blower to turn off (at 200 °F)
On the black rim that encircles the silver-colored dial, there is a small notch in the 6 o’clock position. As the dial turns clockwise, the point indicators on the silver-colored dial align with that notch, causing the blowers to turn on and off. The dial is activated by the heat in the furnace.
So, imagine this: You start a fire in the furnace. At this point, the air around the fan limit control is at room temperature — say, 50 °F. As the fire heats up, though, so does the air around the fan limit control. At the same time, the thermostatically controlled draft blower turns on and warms the fire.
As the air around the fan limit control heats up, it causes the silver dial to rotate clockwise. Once the air around the fan limit control reaches 150 °F, the middle point indicator on the dial aligns with the notch in the 6 o’clock position, and the distribution blower kicks on, ready to distribute heat.
If the fire in the firebox burns too hot and the air around the fan limit control exceeds 200 °F, the rightmost point indicator on the dial will align with the notch in the 6 o’clock position, turning the draft blower off. This is a protective measure designed to prevent the furnace from burning too hot.
As the fire simmers and the air around the fan limit control cools, the silver-colored dial will turn counterclockwise. Once the air cools to around 100 °F, the leftmost point indicator will align with the notch at the 6 o’clock position, and the distribution blower will turn off. At this point, it’s time to add more wood to the firebox (or, if it’s warm enough outside, to let the fire burn out).
Fire Chief and Shelter Furnace FAQs and Troubleshooting
Thermostat Installation
The Fire Chief FC1000E and Shelter SF1000E come with a Honeywell thermostat. We do not provide thermostat wire for installation, though. That needs to be bought separately.
You may install the wall-mounted thermostat in the most convenient location possible for you; just ensure that you’ll be able to run thermostat wire from the thermostat to the furnace’s location (e.g., through your wall or floor).
You’ll notice that the thermostat has 3 connection points while the furnace only has 2. On the thermostat, install the thermostat wire to the R and W connection points (the C connection point is for an optional battery backup and is not necessary for the FC1000E and SF1000E models).
The thermostat wire terminals on the furnace are labeled R and W to allow you to match the wire properly to their respective R and W terminals on the thermostat.
Firebrick Layout
During the shipping process, it’s not uncommon for the firebrick inside the furnace to shift. The furnace features brick in two locations: on the bottom of the firebox and in the upper chamber of the firebox.
The bottom of the furnace comes with 2 types of brick (in 3 distinct sizes):
- 12 clay firebricks (9” x 4-½” x 1-¼”)
- 2 vermiculite bricks (4-½” x 3-⅛” x 1-¼”)
- 2 vermiculite bricks (5-⅞” x 4-½” x 1-¼”)
Here is a diagram of the optimal firebrick orientation in the bottom of the firebox:
The top chamber of the firebox is lined with vermiculite brick in 2 distinct sizes:
- 8 vermiculite bricks (9” x 4-½” x 1-¼”)
- 2 vermiculite bricks (9” x 2-3/16” x 1-¼”)
Here is a diagram of the optimal firebrick orientation in the top chamber of the firebox:
Should your firebrick shift during shipping or should you need to replace your firebrick, refer back to these diagrams to position the brick correctly.
Odor During Initial Firing of Furnace
When you fire your furnace for the first time, you may notice a smell lingering in the air.
This is completely normal.
The steel of the furnace is oiled during the manufacturing process. As the furnace heats up, the unit reaches temperatures high enough to vaporize the oil residue remaining on the unit.
The smell should dissipate after a few hours of usage.
Flames Emitting from Furnace Door during Reloading
In some instances, you may experience flames discharging from the fuel door when opening it to add more wood. If this happens, there are a few problems that could be causing it.
For one, opening the door provides additional oxygen to the firebox. This additional oxygen winds up igniting any accumulated gasses from partially spent wood fuel. To remedy the issue, always open the door slowly, unlatching it partway first before opening the door fully.
Excessive flames may also be caused by overfilling the combustion chamber with wood fuel. Be sure not to open the furnace until the larger load of wood has had time to burn through.
Common Distribution Blower Problems
During the operation of your FC1000E or SF1000E, you may run into a few issues with your distribution blower. We’ll address them all one-by-one here.
Distribution Blower Runs Constantly
If your distribution blower is running constantly, it’s possible that the white button on the fan limit control is pressed in. This button manually runs the distribution blower. To switch back to automatic mode, pull the white button on the fan limit control out.
It’s also possible that the “OFF” setting on the fan limit control is too low. To check this, remove the cover on the fan limit control and ensure that the point indicators described in the section above are set to 100 °F for “OFF” and 150 °F for “ON”.
In some cases, the fan limit control itself may be defective. To check this, move the “ON” and “OFF” point indicators to a position where the blower should turn off (e.g., setting the “OFF” position as low as 40 °F). If the blower continues to run, you’ll need to replace the fan limit control. After this test, be sure to put the point indicators back to 100 °F and 150°F.
Finally, a continually running distribution blower may be caused by improper wiring. Review the wiring diagram on page 18 of the owner’s manual to ensure the wiring is correct.
Distribution Blower Runs Won’t Run
If your unit’s distribution blower won’t turn on, start by verifying that the wall thermostat is in the “HEAT” position and that its batteries are properly installed.
If the problem still persists, you may have a defective thermostat. To check, turn the thermostat to a temperature setting that is higher than the current temperature in your home. If the distribution blower does not turn on, the thermostat may be defective and need to be replaced.
It’s also possible that there is a defective relay or transformer in the distribution blower (or that the entire distribution blower is defective). If that’s the case, you’ll need to replace the entire distribution blower.
Common Draft Blower Problems
There are a few issues that sometimes occur with the draft blower over the normal course of operation of a Fire Chief FC1000E or Shelter SF1000E. Here is a list of those common problems and several applicable solutions.
Draft Blower Runs Constantly
If your furnace’s draft blower won’t stop, it’s possible you may have a defective thermostat. To check, set the thermostat to a lower temperature setting than the temperature in your home. If the draft blower continues to run, your thermostat may need to be replaced (or rewired).
It’s also possible that your home simply isn’t being supplied with enough heat to satisfy the wall thermostat. If you believe this is a possibility, consult a professional to determine the proper furnace size and insulation factor of your home.
In other cases, the draft blower may have a defective relay or transformer. If this is true for you, replace the defective relay or transformer.
Draft Blower is Puffing Smoke
If smoke from the firebox is puffing back through the draft blower, this may be because the furnace is not connected to return air and is drawing smoke fumes from the flue. If this is the case, connect return air to your duct system.
The horizontal run that connects your furnace to your flue may also be too long. Ensure that this horizontal run does not exceed five feet and that there are two inches of rise for every foot of horizontal run.
It may also be possible that the horizontal connection is utilizing too many elbows. Be sure never to utilize more than two elbows when installing the horizontal run.
Finally, there may be negative pressure in the furnace area caused by a combination of running the unit and not allowing enough airflow to the furnace area. Allowing more fresh air into the room from the outside can help to remedy the issue.
Excessive Smoke During Reloading
If smoke rolls back into the room when you load more wood into the furnace, it’s possible that the horizontal run that connects the furnace to the chimney flue is too long. Again, be sure not to exceed five feet of run, and be sure to allow for two inches of rise for every one foot of run.
The problem may also be caused by an insufficient draft. To prevent this, ensure your furnace utilizes one of the following:
- A clay-lined masonry chimney
- A masonry chimney with a 6-inch stainless steel liner
- Metal all-fuel Class A HT2100 chimney pipe
Insufficient draft may also be caused by improper chimney height. Ensure that the chimney extends at least three feet above the highest point where it passes through the roof surface and is at least two feet higher than any part of the building within a horizontal distance of ten feet.
Excessive smoke may also be caused by negative pressure in the furnace area. If this is the case, simply allow more fresh air to flow into the room.
Home Isn’t Heating Up Sufficiently
If your home isn’t heating up sufficiently, there may be several causes. For one, it’s possible that the furnace isn’t properly connected to your home’s ductwork. You can either refer to the manual to understand proper ductwork connection procedures, or you can contact an HVAC professional.
It’s also possible that the combustion chamber is not receiving enough oxygen to keep the furnace burning hot enough. This is often caused by the furnace being installed in a room that’s too airtight. Simply vent the room and supply a bit more fresh air to fix the problem.
In some cases, the air filter in the back of the furnace may be too dirty, restricting airflow. Simply replace the filter. Also, using less restrictive, low-cost filters is actually better for a wood furnace in order to allow enough air to pass through.
Finally, be sure you’re not using wet or unseasoned wood fuel. Wood furnaces work best using low-moisture firewood that’s been seasoned for six months to a year.
Downdraft on Chimney
If your chimney is experiencing downdrafts, it may be because your flue has a cold spot that’s inhibiting exhaust discharge from rising properly. This is common in factory-built flues in which the insulation has settled or a seam has ruptured. Be sure to repair or replace as needed.
The problem may be as simple as an outside obstacle (like a tree branch) prohibiting exhaust byproducts from rising properly. In this case, just remove the obstacle.
Finally, downdrafts may be caused when the flue is located too close to the peak of the roof (or if it fails to rise above the peak). If this is true for your chimney, increasing its height can solve the problem.
Furnace Door Won’t Seal Properly
If your furnace’s door isn’t getting a tight enough seal, it’s possible that the rope gasket inside the door has lost its pliability over time. It’s not necessarily that the gasket has failed; it’s just that it’s been compressed so many times that it’s lost some of its spring.
Luckily, the door latch on FC1000E and SF1000E furnaces is adjustable. Simply loosen the two nuts on the bottom of the latch, slide it back a few centimeters, and tighten them again. Then close and lock the door. If it’s still not tight enough, adjust the latch again until it’s snug.
Creosote Buildup in Chimney Flue
There are several reasons creosote may be accumulating in your furnace’s chimney. Wood with high resin or moisture contents can cause rapid creosote buildup. These kinds of wood should be avoided. Instead, burn seasoned hardwood to ensure a clean, low-creosote burn.
Creosote may also be caused by an insufficient draft. Again, be sure your furnace is connected to a masonry chimney, a masonry chimney with a 6-inch stainless steel liner, or a metal all-fuel Class A HT2100 chimney pipe. Never use uninsulated stove pipe for your furnace’s chimney flue.
Also, make sure the chimney is at least three feet above the highest point where it passes through the roof surface and at least two feet higher than any part of the building with ten feet horizontally.
It’s possible that a bad connection or a structural defect in the chimney itself is causing an air leakage, leading to the formation of creosote. Inspect the entire flue from the exhaust stack all the way up to the chimney cap and make any necessary repairs.
Finally, creosote may also form when the firebox isn’t receiving an adequate amount of oxygen. This occurs when the room the furnace is in is too airtight. Supplying more fresh air to the furnace room will help the fire burn hotter, helping to eliminate creosote.
Additional Questions or Other Furnace Problems
This has been a look at some of the most common issues homeowners tend to have with their Fire Chief FC1000E and Shelter SF1000E wood-burning furnaces. While this guide is in-depth, it’s not at all comprehensive.
If you have any other questions about the operation of your furnace or any issues we haven’t covered here, be sure to reach out to our customer service team. They’ll be able to help you address any issues you’re having to get your furnace working properly again.
