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We recommend using insulated chimney for optimum performance, if you choose to use single wall
stainless, the flue temperature will be reduced which promotes the formation of creosote, possibly
creating a fire hazard. If you use single wall stainless pipe, minimum clearance is 18” from combus-
tibles.
DO NOT
use Galvanized or Black Pipe to vent your furnace it will rust out.
When installing the furnace maintain the “10/2 Rule” for the flue - the chimney cap must be
2’ (two feet) higher than any part of the building within a horizontal distance of 10’ (ten feet). Refer to
Drawing:
Hot Air Duct and Cold Air Return:
Included with your OS2200: 25’ of ten inch I.D. flexible
insulated hot air duct and 25’ of twelve inch O.D. flexible cold air return duct. Connect with 4
clamps provided
The factory supplied insulated flexible hot air duct on the OS2200 is ten inch (10”) - do not
attempt to reduce this dimension by any means - doing so would greatly affect the performance and
efficiency of the furnace. The factory supplied flexible cold air return is twelve inch (12”) and should
not be reduced. The cold air return must be connected to the home in every installation - failure to do
so will cause pressurization of the home and the furnace will not function.
NEVER
draw cold outside
air into the blower housing - by doing so the furnace’s heat chamber temperature will not reach a level
necessary to heat the house.
Duct work should be designed so the external static pressure does not exceed .02 water column
inches while developing air velocities of 600 feet to 1,000 feet per minute in the main trunk duct and
400 feet to 600 feet per minute at the registers. The heat outlet area should never be less than 10"
round.
The Fire Chief OS2200 MUST be installed with a cold air return system
. The system must be a
minimum of 12” to readily transfer the cold air back to the furnace. If desired , a cold air filter box may
be constructed, minimum opening 226 square inches.
Burying Duct Work
: FLEX DUCT WORK CAN NOT BE EXPOSED TO THE ELEMENTS -
The flex duct provided with the furnace must be encased in a weathertight enclosure above
ground. To bury duct work below ground, use schedule 40 or 80 PVC rather than the flex provided
with the furnace. Dig a trench to place both the heat duct and cold air return. The trench must be a
minimum of 24” deep. To further insure efficiency, the trench may be lined with 1” (one inch) pink
styrofoam sheeting insulation on the sides and bottom to prevent heat loss and moisture formation.
10’
2’
