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The instructions in this section on venting must be followed to avoid choked combustion or recirculation of
flue gases. Such conditions cause sooting or risks of fire and asphyxiation.
Heater must be protected from freezing downdrafts during shutdown periods.
Remove all soot or other obstructions which will retard free draft from chimney.
Venting materials used for this category 1 appliance must be in accordance with the National Fuel Gas
Code and all state and local requirements.
NOTE: A NEGATIVE DRAFT MUST BE MAINTAINED IN VENT PIPING (-0.02 to -0.06 inches water
column).
A. VENT CONNECTOR
The chimney vent connector diameter should be the same size as the heater flue outlet.
A minimum rise of 1/2
” per foot of horizontal connector length must be maintained between the heater
and chimney opening. The connector length should be kept as short as possible.
B. BAROMETRIC DRAFT CONTROL ASSEMBLY
A double-acting barometric draft control assembly is necessary for this unit. The installer may choose the
direction of the outlet to the draft control assembly. This assembly must be fitted to the jacket cover such
that it is plumb and level to the ground. Fasten the draft control assembly to the top cover using sheet
metal screws at three or more locations, as required.
Refer to the instructions provided with the barometric damper for installation requirements.
Figure 3
– Barometric Draft Control Assembly
Dampers or other obstructions must not be installed between the heater and the barometric draft control
assembly.
Vent connections must be made to an adequate stack or chimney. Refer to the National Fuel Gas Code
or to
the vent pipe manufacturer’s gas vent and chimney sizing table to properly design and size the
venting system.