Midco E20BP - Manual (Page 3)

-3-
FIGURE 2 Wet Base Boiler with Unlined
Combustion Chamber
Maximum Firing Rate
100 MBH
143 MBH
195 MBH
225 MBH
Vent Pipe Diameter
5"
6"
7"
8"
TABLE 1 Recommended Vent Pipe Sizes
FIGURE 3 Draft Hoods
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
gravity 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-STANDARD 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 and pilot assembly are free of foreign materials,
and also that the spark electrode assembly has not been
damaged or displaced. See Figure 6.
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 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
sufficient 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 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 material 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 equipment in such a
manner as to prevent any difference in the pressure between
the hood or regulator and the combustion air supply. 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,
installed and adjusted in accordance with the manufacturerÕs
instructions, if approved by Local Codes.
■ 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.
FIGURE 4: Barometric Dampers
Figure 3 and 4: Copyright by the American Gas
Association. Used by permission of the copyright holder.