Midco DS45B - Manual (Page 4)

V Electrical
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
manufacturer’s 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 manufacturer’s instructions.
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Installation wiring and grounding of the burner must conform to local codes, or, in their
absence in the United States to National Electric Code, ANSI/NFPA No. 70- latest edition;
in Canada, to Canadian Electrical Code Part 1, CSA Standard C22.1.
Use copper wire not less than 14 gage for line voltage wiring. Be sure to hook up to
permanently live circuit. Provide a fused on-off disconnect switch carrying a minimum 3
amp fuse.
4
Part 1 Installation
Part 1
Installation
Continued
IV Chimney, Vent
Connector*, and
Draft Control
Continued
250 MBH
320 MBH
400 MBH
7”
8”
9”
Maximum
Input
Flue Pipe
Diameter
Table 1: Recommended
Vent Connector Sizes
Figure 4: Wiring Diagram