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Step 3. Negative Pressure Make-up Air
Negative Pressure warning
: When negative pressure is
present, an atmospherically vented fireplace (with a draft
hood) may not function properly and it may down draft. In
the case of a gas appliance, spillage of the combustion
gases may occur.
This may create a dangerous carbon
monoxide situation in the house.
The causes of negative pressure to a house can include
the following:
Stack effect in the building.
Exhaust only appliances (mechanically and
atmospherically vented).
Inadequate make-up air (which is increasingly
more prevalent in new construction).
NOTE:
This fireplace will operate correctly only if adequate
ventilation is provided to allow proper draft to the fireplace
system. Heat-N-Glo assumes no responsibility for the
improper performance of the fireplace system caused by
inadequate draft due to environmental conditions, down
drafts, tight sealing construction of the structure, or
mechanical exhausting devices which create a negative air
pressure within the structure where the fireplace is located.
It is recommended that all natural venting non-air tight gas
fireplaces have outside air connected to them. It is also
recommended that the building be mechanically or passively
balanced to allow atmospherically vented appliances, such
as top vented gas fireplaces with draft hoods, to draft
properly. If the home experiences negative pressure or is
likely to experience negative pressure, connection to an
outside air source is mandatory.
Installing Optional Outside Make-up Air:
This unit is equipped to accept outside air. By using outside
make-up air, the amount of room air used for combustion
will be reduced. It is recommended that an AK-TV air kit be
used with this appliance.
WARNING: IN A NEGATIVE PRESSURE CON-
DITION (LIKELY TO OCCUR IN NEW HOMES
THAT DO NOT HAVE ADEQUATE MAKE-UP
AIR) THE OUTSIDE AIR KIT MUST BE IN-
STALLED TO OBTAIN PROPER PERFOR-
MANCE AND TO HELP PREVENT SPILLAGE
OF COMBUSTION GASES.
Air Damper
Before lighting the burner, open the damper. Close the
damper when the burner is off.
Detailed installation instructions for Model AK-TV Outside
Air kit are found in the kit.
Figure 4. Make-up Air
!
A 4-inch side collar/damper (found in AK-TV Kit) must be
installed on the fireplace by attaching the side collar to the
outer wrap of the fireplace at the right-hand rear corner using
sheetmetal screws. See Figure 4. Attach one end of a 4-
inch flexible air duct (not provided in the AK-TV Kit) to the
side collar and the other end of the duct to the make-up air
termination cap. Use plastic tie straps to secure the ends
of the flex duct to each collar.