Vertical Directaire Venting W/Rooftop Combustion Air; Air Inlet Pipe Materials - Lochinvar Power-Fin Series Installation And Service Manual

venting flue products to the outdoors.
installation requirements must be followed.
The maximum installed length of the Category IV flue from the
appliance to the point of termination must not exceed 50
equivalent feet in length. Subtract 5 feet of equivalent length
for each 90° elbow installed in the vent. Subtract 2 1/2 feet of
equivalent length for each 45° elbow installed in the vent.

Air Inlet Pipe Materials

A DirectAire Vent System always requires the installation of an
additional pipe to supply combustion air from outdoors directly
to the appliance. The air inlet pipe must use one of the
materials specified in the Air Inlet Pipe Materials section.
In cold climates, the use of Type "B" double-wall vent pipe or
an insulated single-wall pipe is recommended to help prevent
moisture in the cool incoming air from condensing and leaking
from the inlet pipe.
CAUTION
Appliances that are shut down or will not operate may
experience freezing due to convective airflow in the air inlet
pipe connected to the appliance.
Sidewall Combustion Air Inlet
The air inlet cap for the sidewall air inlet must be purchased
from the appliance manufacturer.
The part numbers for the required sidewall air inlet cap kit are
listed by unit size. The appliance manufacturer, in accordance
with CSA International/CGA requirements, must furnish the
sidewall air inlet cap. Each kit includes the special combustion
air inlet cap for installation on an exterior sidewall for
operation of a single appliance only.
Flue piping from the appliance to the rooftop termination may
be increased to 8 inches or 10 inches based on field availability
of 7 inch and 9 inch flue material.
TABLE — E
Vertical DirectAire Vent Kits
Input Flue Alt.
Btu/hr Size Flue
500,000 7" 4"
750,000 9" 5"
1,000,000 10" 6"
1,300,000 12" 8"
Location of a Sidewall Air Inlet Ca\p
Incorrect installation and/or location of the air inlet cap can
allow the discharge of flue products to be drawn into the
combustion process on the heater. This can result in incomplete
combustion and potentially hazardous levels of carbon
monoxide in the flue products. This will cause operational
All other general
Alt. DirectAire
Vent Inlet Inlet
Reducer Pipe Sidewall
Size Cap Size Kit
DRH2435 5" SAK3003
DRH2436 5" SAK3003
DRH2437 6" SAK3000
DRH2438 6" SAK3000
problems with the heater and possible spillage of flue products
that can cause personal injury, death, or property damage.
The termination point of the sidewall air inlet must be installed
a minimum of 12 inches (0.30m) above ground level and above
normal levels of snow accumulation.
The point of termination for the sidewall combustion air inlet
cap MUST be located a minimum of 3 feet (0.91m)
horizontally and 12 inches (0.30m) below any point of flue gas
termination (vent cap) if it is located within a 10 foot (3.05m)
radius of the flue outlet.
The sidewall combustion air inlet cap MUST NOT be installed
above the sidewall flue outlet if it is located within a 10 foot
(3.05m) radius of the flue outlet.
The sidewall combustion air inlet cap must not be installed
closer than 10 feet (3.05m) from an inside corner of an
L-shaped structure.
The sidewall combustion air cap assembly used MUST
adequately protect the combustion air inlet from wind and
weather.
The sidewall combustion air inlet cap and the rooftop flue gas
outlet are located in different pressure zones in a DirectAire
system.
Combustion air supplied from outdoors must be free of
contaminants (see Combustion and Ventilation Air). To prevent
recirculation of flue products into the combustion air inlet,
follow all instructions in this section.
For clearances between multiple vent caps, see the Multiple
Horizontal Direct Vent Installation section.
HORIZONTAL DIRECTAIRE WITH
VERTICAL COMBUSTION AIR
This vent option is only available on units with modulating
burner firing. The unit can be identified by the "Category IV"
and the "M" prefix on the firing controls as noted on the unit's
rating plate.
FIG. 18 Horizontal DirectAire Installation with Rooftop
Combustion Air Inlet
The Horizontal DirectAire System terminates the flue at the
sidewall using Category IV vent materials and a combustion air
inlet pipe to draw air from the rooftop. Horizontal DirectAire
16