Rooftop Combustion Air Inlet
(PF0501-1300 ON/OFF Models - Only)
The flue outlet and combustion air inlet
terminate in the same pressure zones, but
when installed with a negative draft,
Category I vent system, does not meet the
specifications of a direct vent system.
DirectAire Horizontal
DirectAire Horizontal vent systems are
installed with the flue terminating at the
sidewall, using Category IV vent materials,
and a separate combustion air inlet pipe at
the rooftop, or at the sidewall to draw air
from the outdoors. The flue outlet and
combustion air inlet terminate in different
pressure zones.
The maximum installed length of the
combustion air inlet pipe and flue gas vent
pipe must not exceed 50 equivalent feet
(15.2m) in length per pipe.
The flue and air inlet sizes for DirectAire
Horizontal systems with Rooftop Air Inlet are
listed in TABLE E. This venting option uses a
rooftop air inlet constructed from materials
purchased locally by the installer or a
sidewall air inlet purchased from the
manufacturer, and a sidewall vent
termination purchased from the manufacturer.
The part numbers for the required sidewall
vent cap kit are listed in TABLE C. The part
numbers for the required sidewall air inlet
cap kit are listed in TABLE D.
DIRECT VENT SYSTEMS
A Direct Vent system uses a flue to the
sidewall or rooftop with a separate
combustion air inlet pipe to the outdoors.
The Direct Vent system terminates the flue
and the combustion air inlet pipe on the
same surface and in the same pressure zone
in one of two configurations.
(1) The flue on the rooftop and combustion
air inlet on the rooftop. (FIG. 17)
(2) The flue on the sidewall and combustion
air inlet on the sidewall. (FIG. 18)
Direct Vent systems require the installation of
specific venting materials. Rooftop flue gas
termination caps and combustion air inlets
must be purchased locally. Sidewall flue gas
termination caps and combustion air inlets
must be purchased from the appliance
manufacturer as per CSA International
requirements.
L o c h i n v a r
D E S I G N E R
’
S
G U I D E
P O W E R
-
F I N
W A T E R
H E A T E R
6 1 5 - 8 8 9 - 8 9 0 0
1 5
Lochinvar
(FIG. 14) DIRECTAIRE VERTICAL W/ROOFTOP AIR INLET
(FIG. 16) DIRECTAIRE HORIZONTAL W/ SIDEWALL AIR
INLET IN A DIFFERENT PRESSURE ZONE
(FIG. 15) DIRECTAIRE HORIZONTAL
W/ ROOFTOP AIR INLET
NOTE:
Units with ON/OFF
burner controls utilize
Category IV vent
material when
installed in
a Direct Vent
configuration.