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GENEVA SERIES B-VENT GAS APPLIANCE
DESIGN AND INSTALLATION CONSIDERATION
When selecting a location for your B-Vent appliance, it is important to evaluate a number of considerations.
Modern construction techniques can create conditions that may not allow your vent to draft properly. This may
result in spillage from your B-Vent appliance, as well as cause other combustion appliances to operate incorrectly.
Tightly sealed construction is important for energy efficiency. Unfortunately, a great deal of effort has been
directed to tightening up sidewall construction, while considerably less attention has been paid to tightening
upper portions of the warm air envelope (insulated ceilings). This has increased the Stack Effect, a condition
that increases the negative pressure generated by the structure. This negative pressure will directly affect the
drafting performance of a B-Vent appliance vent. To minimize the negative pressure generated by stack effect,
make certain that all ductwork installed in the attic spaces is sealed airtight. Minimize the number of recessed
light fixtures installed in the insulated ceiling and use sealed recessed light fixtures. Finally, make certain the
whole house fans and attic access panels are tightly sealed. These are important design considerations that
must be observed during the design and construction stage of the home.
If you desire to put an appliance in your basement, we recommend that you consider a direct vent gas appliance.
Basements always have a significant negative air pressure that causes the B-Vent system to be more susceptible
to spillage and cold flue backdrafting. Since direct vent gas appliances are sealed, they are not affected by the
negative pressure that exists in basements.
Finally, a B-Vent appliance performs best when the vent (roof termination) is located on the upper half of the roof,
especially when cathedral ceilings are present. Vents that are located on the lower half of the roof realize what is
known as lazy flue and will not draft as well as a vent that is located in the upper portion of the roof. The reason
for this is that the stack effect generated by the overall height of the living spaces inside the house will exceed the
draft generated by the vent system. If you desire to place an appliance in a location where the termination cap
would be located on the lower half of a roof; such as on an outside wall at the base of a cathedral ceiling, we
recommend that you consider using a direct vent gas appliance. This will ensure an appliance that operates
correctly.
These properties do not affect just your B-Vent appliance. They can cause any woodburning fireplace as well as
any conventionally vented (B-Vent) gas appliance to operate improperly. Careful planning at this stage of your
project will ensure satisfaction with the operation of your appliance once it is completed.