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inch of flow area for each 4000 BTU/H of heater input. If
air is provided through horizontal ducts, each opening and
duct must provide one square inch of flow area for each
2000 BTU/H of heater input. These requirements are
summarized in Table 2. Note that the specified areas are
net free area, after allowing for the blockage of grill bars,
etc. See applicable codes for details.
Even though local codes may allow it, Waterpik
Technologies does not recommend installation in which
combustion and ventilation air is provided by infiltration.
Pool heaters tend to have larger input than many
appliances and it is best to specifically provide combustion
air means.
Table 2. Air Openings to Outside
Required Net Free Open Area
for Combustion Air Openings
Direct from outside Duct from outside
Model in
2
(cm
2
)in
2
(cm
2
)
250 63 (406) 126 (813)
400 100 (645) 200 (1290)
2F-4. Exhaust Venting
2F-4a.Important Information on Vent
Pipe Sizing
When converted to indoor venting configuration, the
LX and LT heaters have a vent collar fitting. The
diameter of the vent collar and, thus, the minimum
diameter of the vent pipe to be used is determined by the
model of heater installed. The only correct procedure for
vent pipe sizing is to do so in accordance with table 3 and
the applicable installation code as stated in the "Danger"
warning below.
Vent pipe diameter must be as required by
the National Fuel Gas Code Z223.1 or the
Canadian Installation Codes for Gas
Appliances CAN 1-B149.1 & 2. Undersize pipe
can result in inadequate venting and oversize
pipe can result in vent condensation. In either
case the result can be release of combustion
products to the indoors. This can cause
serious injury or death by carbon monoxide
poisoning or asphyxiation.
2F-2. Special Location Requirement
Virtually all local installation codes require that a
heater installed in a garage or similar structure be on a
platform at least 18 inches (46 cm) above the floor. This
requirement is in consideration of possible existence of
combustible fumes at floor level. Consider such
installations carefully and do not proceed if there is any
possibility of such fumes being ignited by the heater.
2F-3. Air For Combustion and
Ventilation
It is very important that the heater be provided with
adequate air for combustion and to ventilate the space in
which it is located. Provide combustion and ventilation air
as specified in local codes, or in their absence per the
National Fuel Gas Code ANSI Z223.1 or the Canadian
Installation Codes for Gas Burning Appliances, CAN 1-
B149.1 & 2.
In general, the codes require that the space in which
the heater is located be provided with two combustion air
openings, one within 12 of the floor and one within 12
of the ceiling (see Figure 6). If air is supplied directly
from the outside, the openings must provide one square
DANGER
Figure 4. Vent Collar Assembly for Indoor Installation.
Figure 5. Vent Pipe Installation.
LX
Model
Vent Pipe Diameter
inch (cm )
250 7.0 17.8
400 9.0 22.9
Table 3. Vent Pipe Sizing Table
INDOOR
VENT
COLLAR
GASKET