Direct Vent Installation of Vent/Air Piping
12
Direct Vent - Multiple Installation - Thru the Roof
1. On installations of multiple MODULATING DELTAS,
terminate each vent and combustion air piping as
described in this manual.
2. The roof penetration of the vent and combustion air
piping should be such that the vent and combustion
air terminations are a minimum 18 inches from the
adjacent vent pipe of the other appliance for instal-
lations in the U.S. as shown in Fig. 8. For installa-
tions in Canada, provide clearances as required by
CSA B149.1 or 149.2.
The combustion air inlet of the MODULATING
DELTA is defined as being part of a direct vent
system. It is not considered as a forced air
intake. The required clearance of an adjacent
appliance vent to a forced air inlet does not
apply in a multiple installation of MODULATING
DELTAS.
NOTICE
12
" M
in.
- 2
4"
12" above
roof or projected
snow line
1
2
"
M
in
.
-
2
4
"
M
a
x
18
" M
in.
Ra
dia
l D
ista
nc
e
A
b
o
v
e
C
o
m
b
u
s
ti
o
n
A
ir
In
le
t
Rain Cap
Vent Termination
Combustion
Air Inlet
Termination
A
n
y
p
o
rt
io
n
o
f
th
e
b
u
ild
in
g
o
r
ro
o
f.
10
Ft.
M
in.
Direct Vent - Multiple Thru The Roof
Termination
Fig. 8:
5. The installer should provide adequate flashing and
sealing boots sized for the vent pipe and combustion
air pipe.
Termination Fittings - Vertical Two Pipe
1. The combustion air pipe termination must include a fac-
tory supplied “bird screen” as shown in Fig. 7 The bird
screen should be inserted inside the termination.
2. The combustion air piping must terminate in an
upside down “U” shape fashion using two 90
º
elbows as shown in Figs. 6 & 7.
3. The vent piping must terminate vertically with a rain
cap as shown in Fig. 6 page 10.
Do not extend the vent pipe outside the roof
beyond the given dimensions shown in Fig. 6,
page 10. Extended exposure of the vent pipe
could cause condensate to freeze and block the
vent pipe.
WARNING
Bird Screen
*
Combustion Air
Inlet Termination
Elbows
*Installer must install the factory supplied “bird
screens” on the combustion air inlet termination.
Direct Vent - Vertical Two Pipe / Combustion
Air Fitting
Fig. 7:
