Installation and Maintenance Manual

Installation: Piping
GTND-SVX01B-EN 33
Z223.1 National Fuel Gas Code. In Canada installation
must be in accordance with CAN/CGA-B149.1
“Installation Code for Natural Gas Burning Appliances
and Equipment” and CAN/CGA-B149.2. “Installation
Code for Propane Burning Appliances and Equipment”.
2. The Concentric Vent Kit (which includes a concentric
vent box, air inlet screen, deflector collar, vent terminal
and inlet air collar) provided with the heater by the
manufacturer must be installed at the termination
point of the combustion air/vent system. Refer to
Figure 32, p. 33 through Figure 36, p. 35 and Tab l e 8,
p. 33.
3. Each unit heater MUST have its own vent system. It
M
UST NOT be connected to other vent systems or to a
chimney.
4. Use flue pipe of the same size as the flue connections
o
n the gas unit heater (see Tab le 1, p. 12). All heaters
must be vented with a single or double wall pipe listed
for Category III positive pressure
vent systems. A
single length of double wall vent pipe must be used to
go through the concentric vent box and outside wall to
the vent terminal.
5. The vent system must be installe
d to prevent collection
of condensate. Pitch horizontal pipes downward 1/
4 inch per foot (21 mm per meter) toward the vent cap
to facilitate drainage. Vertical vent pipes should be
piped as depicted in Figure 34, p. 34.
6. The equivalent lengt
h of the vent system must not be
less than 5 feet (1.5 m) and must not exceed 30 feet
(9 m). The equivalent length equals the
total length of
straight pipe plus 5 feet (1.5 m) for each 90° elbow and
2.5 feet (0.76 m) for each 45° elbow.
7. Each slip joint must be secured with at least three
cor
rosion resistant screws. Two full turns of 3M #425
Al
uminum Foil tape or its equivalent must then be
used to seal each joint. High temperature silicone
sealant may be used instead of the tape. Silicone
sealant must be used to seal the joint between the
Type B vent pipe and the single wall pipe.
8. For horizontal vent systems longer than 5 feet (1.5 m),
th
e system must be supported from overhead building
structures at 4-foot (1.2-m) intervals in the U.S. and at
3-foot (0.91-m) intervals in Canada.
9. The exhaust vent system m
ust remain at a minimum
distance of 1 inch (25 mm) from all combustible
mate
rials. Any part of the vent system that passes
through a combustible material must be properly
insulated.
Note: Increa
sing the clearance distances may be
necessary if there is a possibility of distortion or
discoloration of adjacent materials.
10. The top of a VERTICALLY VENTED exhaust system
must ex
tend at least 3 feet (0.91 m) above the roof
surface that it passes through (see Figure 34, p. 34).
11. The point of termination for a HORIZONTALLY VENTED
exhaust
system must be at least 12 inches (0.3 m) from
the exteri
or of the wall that it passes through. In
addition, the termination point must be at least 1 foot
(0.3 m) above grade or above the
snow line, more than
6 feet (1.8 m) from the combustion air inlet of another
appliance, at least 4 feet (1.2 m) below, 4 feet (1.2 m)
horizontally from, or 1 foot (0.3 m) above any door,
win
dow or gravity air inlet into any building, and more
than 3 feet (0.91 m) from and not directly above, any
g
as meter or service regulator. Refer to Figure 35,
p. 34, Figure 36, p. 35, and Ta b l e 6, p. 24.
Table 8. Unit sizes 30–120: Concentric vent box
dimensions
Unit Size
Dimensions—Inches (Nominal)
A B C D E G
30
4-1/2 4 6 8 5 12
45
60
75
90
5-1/2 5 8 12 5 15105
120
Figure 32. Unit sizes 30–120: Concentric vent box