Midco DS24A - Manual (Page 3)

III Combustion Chamber
Continued
IV Chimney, Vent
Connector*,
and Draft Control
*Formerly referred to as Flue Pipe
3
■ ■ ■ ■ In the case of wet base boilers, where the entire combustion chamber is comprised of heat
exchange surfaces and no combustion chamber liner was provided for oil firing, a liner is usually
not required for the ECONOMITE. However, a liner or target wall may be necessary if the combus-
tion chamber is unusually short, in order to avoid
flame contact on the heat exchanger walls or
flueways.
■ ■ ■ ■ If a built up chamber liner is required, use
2300°F minimum insulating material.
■ ■ ■ ■ The burner tube, or the stainless steel sleeve
that is included with the burner, must be sealed
air tight into the combustion chamber liner open-
ing with refractory material as shown by Figures
1 and 2. The sleeve is preferred as it is designed
to properly locate the end of the tube relative to
the inside wall of the combustion chamber, and
to permit burner removal without breaking the
seal.
CAUTION: In no case should the burner
tube be allowed to extend into the chamber
proper; it must be set at least 1" short of the
inside surface.
■ ■ ■ ■ Special heat resistant alloy extension tubes and instructions are available for those applications
where the burner tube is too short to reach the combustion chamber (such as old-fashioned grav-
ity warm air furnace installations).
WARNING: Burner cabinet must be
mounted in orientation shown in Figures 1
and 2. Any other mountings may cause a
dangerous condition, and will void burner
warranty and agency approvals. Non-stan-
dard arrangements may be available for
some models; consult factory for details if
required.
■ ■ ■ ■ Before permanently setting the burner in
place, check that the nozzle ribbon is free of for-
eign materials and also that the electrodes have
not been damaged or displaced, see Figure 7.
WARNING: The chimney shall be inspected for unsafe conditions such as deteriorat-
ed masonry and excessive soot or other blockage or potential blockage. Installation
must conform with local codes or in the absence of local codes with ANSI Z21.8 latest
edition and NFPA, ANSI Z223.1 latest edition.
WARNING: The Vent Connector shall not be connected to a chimney already venting
solid fuel burning equipment, an incinerator or an open fireplace.
■ ■ ■ ■ The Vent Connector shall be made of non-combustible, corrosion resistant material capable of
withstanding the vent gas temperature produced by the gas utilization equipment and of suffi-
cient thickness to withstand physical damage.
■ ■ ■ ■ The Vent Connector shall be as short as possible. The
entire length shall be readily accessible for inspection,
cleaning and replacement.
■ ■ ■ ■ The length of horizontal uninsulated Vent Connector
between chimney and a single gas utilization equipment
shall not exceed 75% of 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
excessive 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 utiliza-
tion equipment.
Figure 1: Dry Base Boiler with Combustion
Chamber Liner (Warm Air Furnace
Construction is Similar)
Figure 2: Wet Base Boiler with
Combustion Chamber Unlined
Maximum
Input
Vent Connector
Dia.
100 MBH
143 MBH
195 MBH
225 MBH
5"
6"
7"
8"
Table 1: Recommended Vent
Connector Sizes
Source: ANSI Z21.8b 1993, Installation
of Domestic Gas Conversion Burners.
For other applications,
consult appropriate standards.