The combustion air supply system has specific
vent material and installation requirements.
The air inlet pipe connects directly to the
water heater to supply combustion air. The
combustion air inlet pipe will be a dedicated
system with one air inlet pipe per water
heater. The air inlet pipe
must
be connected
to a combustion air inlet cap.
To prevent recirculation of flue products from an
adjacent vent cap into the combustion air inlet,
follow all applicable clearance requirements in
the latest edition of the
National Fuel Gas Code
and the following instructions:
The combustion air inlet cap
must
be installed
at least 1 foot (0.30m) above ground level and
above normal snow levels.
The point of termination for the combustion air
inlet cap
must
be at least 3 feet (0.91m) below
the point of flue gas termination if it is located
within 10 feet (3.05m) of the flue outlet.
The combustion air inlet cap
must
not be
installed closer than 10 feet (3.05m) from an
inside corner of an L-shaped structure.
Both the combustion air inlet cap and the
powered vent cap/inline fan vent hood
must
be installed on the same wall and in the same
pressure zone.
The Horizontal DirectAire system requires
installation of a single wall pipe to supply
combustion air from outdoors directly to the
water heater. The use of double wall vent
material is recommended in cold climates to
prevent the condensation of airborne moisture.
For models CF401-751, maximum total
equivalent length of the vent pipe and
combustion air inlet pipe cannot exceed
50 equivalent feet (15.24m). Models
CF991-2071 allow a maximum total equivalent
length of 100 feet (30.48m)
for each pipe. Subtract 5 feet (1.52m)
for each elbow in the vent.
Power DirectAire
®
Horizontal Kits
Models CF401-751 vent kit includes the
powered sidewall fan/cap, proving switch, air
inlet cap and all necessary relays to interlock
with the water heater control system. Lochinvar
must
furnish this vent kit in accordance with
CSA International requirements.
Models CF991-2071 vent kit includes the inline
fan, exterior vent hood, a tapered vent adapter,
barometric damper, proving switch, air inlet cap
and all necessary relays to interlock with the
water heater control system. Lochinvar
must
furnish this vent kit in accordance with CSA
International requirements.
The installer supplies all vent pipe
material.
Lochinvar
12
L o c h i n v a r
D E S I G N E R
’
S
G U I D E
C O P P E R
-
F I N
I I
W A T E R
H E A T E R
6 1 5 - 8 8 9 - 8 9 0 0
(TABLE E) POWER DIRECTAIRE
®
HORIZONTAL
KIT PART NUMBERS
MODEL
FLUE SIZE
DIRECT AIR
HORIZONTAL
NUMBER
INLET SIZE
DIRECTAIRE KIT
CF401
6
”
6
”
HDK3031
CF501
6
”
6
”
HDK3031
CF651
8
”
8
”
HDK3032
CF751
8
”
8
”
HDK3032
CF991
10
”
10
”
HDK3026
CF1261
12
”
12
”
HDK3027
CF1441
12
”
12
”
HDK3027
CF1801
14
”
12
”
HDK3028
CF2071
14
”
12
”
HDK3028
