7
For installations with a parallel flow arrange-
ment, the furnace must be equipped with a
damper to prevent cold air from being dis-
charged up around the heat exchanger. Cold air
causes condensation inside the exchanger and
can cause it to rust out which can allow products
of combustion to be circulated into the living
area by the furnace blower resulting in possible
asphyxiation. An air flow activated automatic
damper, P/N 7900--6771, is available from fur-
nace manufacturer.
WARNING
Fire or asphyxiation may result if wrong roof jack is
applied, or if the flue pipe and combustion air pipe
have not been pulled down and secured to the top
of the furnace with sheet metal screws.
CAUTION
Use of furnace or air conditioning components that
are not included in the Underwriter’s Laboratories
certification of this appliance may create a hazard,
will invalidate the certification, and will in many
states make installation illegal. UL listed air condi-
tioning components are specified on the furnace
label.
