38
OPTIONAL CONFIGURATION FOR COMBUSTION
AIR INLET PIPE
In applications where there is a risk of excessive moisture
entering the combustion air inlet pipe, a moisture trap may be
added to the inlet pipe to help prevent moisture from entering
the furnace from the combustion air inlet pipe. See Fig. 41.
When sizing venting systems, the equivalent length of the
optional moisture trap (15 feet/5 M) must be taken into
account.
NOTICE
EXAMPLE FOR
UPFLOW INSTALLATIONS.
MAY BE APPLIED TO
OTHER CONFIGURATIONS.
A12220
Fig. 39 -- Sample Inlet Air Pipe Connection for Polypropylene
Venting Systems
FURNACE
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
NOT IN
HORIZONTAL
SECTION
A93034
Fig. 40 -- Combustion Air and Vent Pipe Diameter Transition Location and Elbow Configuration
Representative drawing only, some models may vary in appearance.
TO CODE--APPROVED DRAIN OR CONDENSATE PUMP
Recommend “T” fitting with 4--inch minimum height standpipe (
A
) of same diameter or larger extending upward.
A
A
A
