32
from and in no case above or below (unless a 4' [1.2 m]
horizontal distance is maintained) electric meters, gas
meters, regulators and relief equipment.
The distance of the vent terminal from adjacent buildings,
open windows and building openings must comply with
the NFGC (U.S.) or B149 (Canada). Gas vents supported
only by flashing and extended above the roof more than 5'
(1.5 m) should be securely guyed or braced to withstand
snow and wind loads.
A
A
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.
A
A
WARNING:
Vent connectors serving any other
appliances shall not be connected into any portion of
mechanical draft systems operating under a positive
pressure. If an XTherm heater is installed to replace an
existing heater, the vent system MUST be verified to be
of the correct size and of Category IV UL Listed stainless
steel vent material construction or other approved
vent materials noted in Table O. If it is NOT, it MUST be
replaced.
NOTE:
For extractor sizing, typical CO2 levels are 9.0%
for natural gas and 10.2% and flue temperature of 150°F
(66°C).
Model
No.
Vent Size
in. (mm)
Volume of Flue
Products (CFM)
1005A
6 (152)
260
1505A
8 (203)
390
2005A
8 (203)
520
*
NOTE: Data for 100% with range between min/max vent length.
Table R.
Volume of Flue Products Data
3.18. Horizontal Through-the-Wall
and Direct Vent (Category IV)
NOTE:
While a drain connection is required in the vent of
all XTherm installations, the drain can be accomplished
in several different ways. The figures in this manual
show the drain in a vent tee, however, this can also be
accomplished using an inline collector for condensing
stacks or an inline vertical or horizontal collector available
from several of the listed vent manufacturers.
A
A
CAUTION:
This venting system may require the
installation of supplemental condensate drains in the vent
piping per the vent manufacturer’s instructions. Failure to
install these condensate drains in the venting system may
cause a non-warrantable failure. Condensate must not be
allowed to freeze. Take appropriate measures.
8' (2.4 m)
OR LESS
TEST POR
T
12" MIN
CONDENSATE
TRAP
CAT IV
VENT PIPE
HEATER
*
HOUSEKEEPING PAD
F10020
2' MIN
(610 mm)
8.5" MIN
(215 mm)
2' MIN
(610 mm)
(305 mm)
* See Figure 6 on page 8.
Figure 35. Vertical Venting Installation
3.17.1. Installation
The maximum and minimum venting length for this
Category IV appliance shall be determined per
Table Q
.
The minimum flue pipe diameter for conventional venting
using Category IV, stainless steel vent is: 6" (152 mm) for
Model 1005A and 8" (203 mm) for Models 1505A and
2005A.
The connection from the appliance vent to the stack must
be as direct as possible and shall be the same diameter
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 terminal. 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 physical damage or separation
of joints. The expected flue pressure is approximately 0.5"
WC positive.
3.17.2. Termination
The vent terminal must be vertical and must terminate
outside the building at least 2' (0.6 m) above the highest
point of the roof that is within 8' (2.4 m). The vent cap
should have a minimum clearance of 4' (1.2 m) horizontally
