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Specifications subject to change without notice.
A10497
Fig. 50 -- Vent Terminations for Ventilated Combustion Air
Recommended Combustion Air Inlet Moisture Trap
Recommended to prevent moisture from trickling into the furnace
vestibule, a trap can be installed in the intake air pipe near the
furnace. To prevent moisture, connecting a drain line to the trap is
recommended as trace amounts of moisture will evaporate into the
intake air stream. If the combustion air inlet is located near a
moisture exhaust duct, or there are other concerns of excessive
moisture being drawn into the combustion air inlet, it is
encouraged to connect a drain line to the trap.
The trap can be constructed from a running tee of the same
diameter of the intake air pipe with
EITHER
a removable cap
attached to a 6-inch long pipe connected to the tee or the External
Vent Trap Kit to help prevent contaminants from entering the
furnace. See Fig. 51.
The External Vent Trap Kit accessory may be used as a trap for the
combustion air inlet pipe if a large amount of moisture must be
removed. The drain line may be connected to the same drain as the
furnace condensate and the evaporator coil condensate line
ONLY
if the inlet air trap drain and the evaporator coil drain empty into an
open segment of pipe above the drain. See Fig.12. When using
the External Vent Trap Kit, refer to those instructions for proper
drain connections.
The tee may also be connected to the intake air pipe on the side of
the casing. See Fig. 51.
In any configuration, it will be necessary to add the equivalent
length of the tee (15 feet/5 M) to the Total Equivalent Vent Length
of the venting system.
The measured length of pipe used in a single or 2--pipe termination
is included in the total vent length. Include deductions from the
Maximum Equivalent Vent Length (MEVL) contained in the
Venting Tables for elbows and flexible vent pipe.
Factory
accessory concentric vent terminations or pipe lengths and elbows
used for “standard” vent terminations (see vent termination figures
associated with Table 13) do not require a deduction from the
Maximum Equivalent Vent Length. Include a deduction for a Tee
when used for Alberta and Saskatchewan terminations.