Rinnai Demand Duo R-Series Installation And Operation Manual page 18

Vent dampers must be certified in accordance
with ANSI Z21.68
Before installing any flue damper, consult the
local gas authority and damper manufacturer for
proper installation.
WARNING
Thermal Operated Vent Dampers: Should NOT
be used with this appliance. This appliance has a
thermal efficiency greater than 80%. This higher
efficiency will result in lower flue gas
temperatures. Such temperatures may be too low
to activate a thermal operated vent damper. Use
of a thermal operated flue damper on this product
may result in spillage of exhaust gases and
ultimately carbon monoxide poisoning.
The entire vent system (combustion air ducts,
louvers, exhaust vent, etc.) must be checked peri-
odically for signs of obstruction, rust, or damage.
If damaged components are observed, they must
be repaired or replaced immediately.
WARNING
This water heater is equipped with a 6 in. vent
adapter and must never be attached to a vent
smaller than 6 in. Certain applications may
require vent diameters greater than 6 in. Consult
your local gas supplier or authority to aid in the
proper vent diameter selection per the
requirements of the vent tables in the current
edition of the National Fuel Gas Code ANSI
Z223.1/NFPA 54, and/or CSA B149.1.
Vent Connectors are relatively short runs of vent,
connecting the appliance to the chimney or
vertical vent run.
Following is a list of appropriate vent connector
material for use between the water heater and the
chimney:
Type B (B-Vent) Double-wall, U.L. listed vent pipe
Type B (B-Vent) Single-wall, U.L. listed vent pipe
Note the following when installing a vent
connector from the appliance to the chimney or
vertical vent:
18
Length:
A vent connector shall be as short as practical
and the appliance located as close as practical to
the chimney or vent. The maximum horizontal
length of the vent connector cannot exceed 75%
of the height of the chimney or vent. Unnecessary
bends should be avoided as to not create
excessive resistance to flow of vent gases.
Single-Wall Vent Connectors:
A single-wall vent connector must not pass
through any interior walls, floors or ceilings. A
single-wall vent connector must not be installed in
attics, crawl spaces or any other confined space
or inaccessible location. Maintain a minimum of 6
in. from combustibles when using single-wall vent
connectors.
Double-Wall, B-Vent:
It is acceptable to pass through walls or partitions
with double-wall, B-Vent.
Slope:
Vent connectors must pitch ¼ inch per foot (21
mm per meter) upward (Figure 8).
Inspection:
The entire length of the vent connector shall be
readily accessible for inspection, cleaning and
replacement.
Joints:
Must be fastened by sheet metal screws or other
approved methods.
Support:
Vent connectors must be supported per the vent
manufacturer's installation instructions to avoid
dips or sags in the vent and maintain the required
clearances.
Figure 8
Demand Duo™ R-Series (REC) Installation and Operation Manual
CHIMNEY OR LISTED VENT
Vent Connector
MIN. ¼ in. (6 mm)
rise per foot
(21 mm per meter)