Fire Chief FCOS1800D, User Manual

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The diagram below shows typical installations through a basement window, crawl space, or wall.  Notice that the heat duct and return air 

duct do not contain any 90° elbows.  The use of 45° or less is advised for proper air delivery.
IF 10 INCH FLEX DUCT IS USED, IT MUST NOT BE EXPOSED TO THE OUTDOORS.  IT IS FOR INDOOR USE ONLY.
WARNING: RISK OF FIRE! DO NOT USE ANYTHING OTHER THAN 250° F-RATED FLEX DUCT!

IMPORTANT:  FOR TECHNICAL SUPPORT OR CUSTOMER SERVICE 

ISSUES, DO NOT RETURN TO THE DEALER (THE DEALER DOES NOT HAVE 

REPLACEMENT PARTS), CALL FIRE CHIEF AT 1-800-875-4788.
TYPES OF INSTALLATIONS:

Your Fire Chief Furnace is designed to be a supplemental or central heating source for your home.  This wood/coal burning furnace may 

be installed in parallel with a properly operating electric, gas, or oil-fired central furnace that is listed or certified in accordance with a 

nationally recognized safety standard within installation clearances as specified on the Fire Chief Furnace nameplate.  When in a parallel 

installation the static pressure of the central furnace plenum may not exceed .15 water column inches, and the maximum setting on 

central furnace limit switch is 182° F.  With the FCOS1800D and FCOS2200D wood and coal burning furnaces in an “Interconnection 

Arrangement” your Fire Chief Furnace should be upstream from the central furnace.  The Fire Chief Furnace warm air supply should 

never be connected to the return air for the central furnace.  A QUALIFIED INSTALLER SHOULD PERFORM INSTALLATION.

CENTRAL DUCT CONNECTIONS:

  A qualified professional should do the installation.  Maximum run should be 25 feet.  A duct run in 

excess of 25 feet will greatly restrict the air flow and heat output, therefore is not recommended.  When connecting the Fire Chief Furnace 

to a central duct system, avoid 90° elbows.  As with any furnace, the more turns and branches in the ducting limit the airflow delivery.  DO 

NOT USE FLEX DUCT OUTSIDE.
Run 10 inch insulated galvanized hot air duct from the outside furnace through a window or wall of the house.  Once inside, you may use 

250º Fahrenheit rated insulated flexible hot air duct to connect the central duct system for the home.  When using flexible duct inside the 

home, it must be pulled tight with no offsets or elbows to prevent turbulence and slowdown airflow.  Connect the duct with a 45° elbow 

or at an angle so the hot air from the Fire Chief Furnace is delivered down stream.  This will ensure proper airflow into the duct system.  

Avoid delivering the hot air through the air conditioning coil, as this will cause an obstruction, reducing the amount of heat output.  DO 

NOT REDUCE THE SIZE OF THE HOT AIR DUCT.  As with any furnace, longer runs and more turns and branches in the ducting greatly 

reduce the airflow and heat output.  Use of 90° elbows is not recommended.
The 12 inch cold air return duct must run to the house to prevent pressurization of the home.  Failure to connect the cold air return will 

cause the furnace not to operate.  NEVER REDUCE THE SIZE OF THE RETURN.  Reducing the size of the cold air return will restrict 

the hot air flow and put excess pressure on the blower motor.  You may terminate the cold air return where you enter the house.  This will 

provide adequate circulation within the home.  See diagram.

RETURN AIR DUCT

SUPPLY DUCT

OPEN/CLOSE 

RETURN DAMPERS

3 PLACES

BACKDRAFT DAMPER

Return Air Duct

Backdraft Damper

Open/Close

Return Dampers

3 Places

Supply Duct