Midco F400-33 - Manual (Page 3)

IV CHIMNEY, VENT CONNECTOR AND
DRAFT CONTROL
WARNING: The chimney shall be inspected for
unsafe conditions such as deteriorated masonry and
excessive soot or other blockage or potential block-
age. Installation must conform with local codes or in
the absence of local codes with NFPA , ANSI Z223.1
latest edition.
WARNING: The vent connector shall not be con-
nected to a chimney already venting solid fuel burn-
ing equipment, an incinerator or an open fireplace.
■ The Vent Connector shall be made of non-
combustible, corrosion resistant material capable of with-
standing the vent gas temperature produced by the gas
utilization equipment and of sufficient thickness to with-
stand physical damage.
■ The Vent Connector shall be as short as possible.
The entire length shall be readily accessible for inspec-
tion, cleaning, and replacement.
■ The length of horizontal uninsulated Vent Connector
between chimney and a single gas utilization equipment
shall not exceed 75% of the the height of the chimney
above the connector, or 100% if the Vent Connector is
insulated.
■ The Vent Connector shall be installed so as to avoid
turns or other construction features which create exces-
sive resistance to flow of vent gas. It shall be installed
without any dips or sags and shall slope upward at least
1/4" per foot.
■ A manually operated damper shall not be placed in
the Vent Connector or chimney of any gas utilization
equipment.
■ The Vent Connector shall be firmly attached to draft
hood outlets and flue collars. Joints between sections of
connector piping shall be fastened by sheet-metal
screws or other approved means. The Vent Connector
shall be supported for the design and weight of the mate-
rial employed to maintain clearance and prevent physical
damage and separation of joints.
■ A draft hood or a barometric draft regulator shall be
installed in the same room or enclosure as the equip-
ment ins such a manner as to prevent any difference in
the pressure between the hood or regulator and the
combustion air supply (see Figures 3 and 4). In no case
shall the relief opening of the draft hood or barometric
draft regulator be located at a point lower than the top of
the highest flue passage in the equipment.
■ Gas utilization equipment requiring controlled draft
may be equipped with a listed double acting barometric
draft regulator, If approved by local codes (see Figure 4).
■ A device which will automatically shut off gas to the
burner in the event of sustained backdraft is required. It
shall be of the listed manual reset type and installed and
adjusted by a qualified service technician in accordance
with the manufacturerÕs instructions.
■ Refer to gas utilization equipment manufacturer for
recommended vent connection requirements.
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FIGURE 3 Recommended Locations forDraft Hoods
FIGURE 1 Dry Base Boiler with Combustion Chamber
Liner (Warm Air Furnace Construction is Similar)
■ Before permanently setting the burner in place, check
that the main burner casting and pilot ports are free of for-
eign materials, and also that the spark electrode assembly
has not been damaged or displaced. See Figure 7.
FIGURE 2 Wet Base Boiler with Unlined
Combustion Chamber