Venting Configurations - Rheem Raypak Hi Delta H Series Installation & Operating Instructions Manual

Venting Configurations

For heaters connected to gas vents or chimneys, vent
installations shall be in accordance with the NFGC
(U.S.), or B149 (Canada), or applicable provisions of
local building codes.
Natural Draft Vertical Venting
(Category I, Fan Assisted)
Installation
Natural draft venting uses the natural buoyancy of the
heated flue products to create a thermal driving head
that expels the exhaust gases from the flue. The nega-
tive draft must be within the range of -.01 to -.08 in.
WC as measured 12 in. above the appliance flue outlet
to ensure proper operation. Vent material must be list-
ed by a nationally recognized test agency.
The maximum and minimum venting length for Cate-
gory I appliances shall be determined per the NFGC
(U.S.) or B149 (Canada).
The diameter of vent flue pipe should be sized accord-
ing to the NFGC (U.S.) and B149 (Canada). The
minimum flue pipe diameter for conventional negative
draft venting using double-wall Type B vent is: 10 in.
for Model 992C; 12 in. for Models 1262C and 1532C;
14 in. for Models 1802C, 2002C and 2072C; and 16 in.
for 2342C.
NOTE: A vent adapter (field-supplied) must be used
to connect Type B vent to the unit.
The connection from the appliance vent to the stack
must be as direct as possible and shall be the same di-
ameter as, or larger than, the vent outlet. The
horizontal breaching of a vent must have an upward
slope of not less than 1/4 inch per linear foot from the
heater to the vent terminal. The horizontal portions of
the vent shall also be supported for the design and
weight of the material employed to maintain clear-
ances and to prevent physical damage or separation
of joints. See table M for Category I venting guidelines.
Termination
The vent terminal should be vertical and should termi-
nate outside the building at least 2 ft above the highest
point of the roof that is within 8 ft. for Model 992C and
10 ft for all other models. The vent cap should have a
minimum clearance of 4 ft horizontally from and in no
case above or below (unless a 4 ft horizontal distance
is maintained) electric meters, gas meters, regulators
8' OR LESS
(MODEL 992B)
10' OR LESS
(ALL OTHER MODELS)
CAT I CERTIFIED VENT PIPE
Fig. 39: Natural Draft Vertical Venting
and relief equipment. The distance of the vent terminal
from adjacent public walkways, adjacent buildings,
open windows and building openings must be consis-
tent with the NFGC (U.S.) or B149 (Canada). Gas
vents supported only by flashing and extended above
the roof more than 5 ft should be securely guyed or
braced to withstand snow and wind loads.
CAUTION: A listed vent cap terminal, adequately
sized, must be used to evacuate the flue products
from the heaters.
Common Venting System
Manifolds that connect more than one heater to a com-
mon chimney must be sized to handle the combined
load. Consult available guides for proper sizing of the
manifold and the chimney. At no time should the area
of the common vent be less than the area of the
largest heater exhaust outlet.
35
(Category I)