Common Venting - Raypak 503A Installation & Operating Instructions Manual

Certified
Model
Material
503A
753A
1003A
Category IV
1253A
UL listed - SS
1503A
1753A
2003A
* Special vent materials are still required.
** Subtract 10 ft per elbow. Max. 4 elbows.
t Adapters supplied by others.
listed - SS vent is: 6 in. (254mm) for Models 503A -
1003A; and 8 in. (305mm) for Models 1253A - 2003A.
The connection from the appliance vent to the stack
must be as direct as possible and shall be the same di-
ameter as 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 termi-
nal. The horizontal portions of the vent shall also be
supported for the design and weight of the material
employed to maintain clearances and to prevent physi-
cal damage or separation of joints.
NOTE: A vent adapter (field-supplied) may be re-
quired to connect the Category IV vent to the heater.
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. The vent cap should
have a minimum clearance of 4 ft horizontally from and
in no case above or below (unless a 4 ft hori-zontal
distance is maintained) electric meters, gas meters,
regulators and relief equipment.
The distance of the vent terminal from adjacent public
walkways, adjacent buildings, open windows and
building openings must be consistent 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 suitable for
connection to the Cat IV vent materials, adequately
sized, must be used to evacuate the flue products
from the building.
Vent Size
Vent Vertical Vent
(in.)
Height
6
8
Table K: Category IV Vertical Venting
Max. Combustion Air
Intake Pipe
1
(Ft)
Material
Galvanized Steel,
75
PVC,
ABS,
CPVC
VENT CAPS STACKED VERTICALLY
FLUE GASES MOVING IN PARALLEL
4'-0" MIN.
(TYP)
DISCHARGE
VENT CAPS ALL AT SAME ELEVATION
FLUE GASES MOVING TOWARD EACH OTHER
VENT CAPS AT STAGGERED ELEVATIONS
FLUE GASES MOVING TOWARD EACH OTHER
Fig. 28: Vent Cap Configurations

Common Venting

The NFGC does not address sizing guidelines for the
common venting of multiple Category IV heaters. This
is covered in the NFGC under "Engineered Vent Sys-
tems". Table L provides boiler discharge vent
pressures at vent pressure switch and volumes of flue
products at full fire for the calculation of appropriate
vent and extractor sizing for common venting.
29
Air Inlet
Max. Length** (Ft)
6" Ø 8" Ø 10" Ø
t
45 100 N/A
N/A 45 85
1" MINIMUM (TYP)
2" MINIMUM (TYP)
DISCHARGE
1" MINIMUM (TYP)
4'-0" MIN.
(TYP)
t