Bradford White PDX1-40S6FBN Installation And Operating Instruction Manual page 17

Venting continued-
Vent terminal configurations for through the wall venting.
When venting through the wall, the exhaust terminal must exit the structure at a
minimum distance of 16" (40.6 cm) from the intake terminal. The exhaust terminal must
not be located below the intake terminal for any reason (see figure 4a below for
examples of acceptable vent terminal configurations).
Figure 4a
CAUTION
NEVER INSTALL AIR INTAKE ABOVE EXHAUST
When local conditions present a risk of ice accumulation on the vent terminals, the
configurations in 4b and 4c or the concentric termination are preferred.
The air intake screen can be removed for cold installations but this may make the air
intake susceptible to debris buildup from birds or other animals. If the air intake
screen is removed to prevent freezing, it is recommended that the air inlet screen be
installed during the spring.
Figure 4b
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