Lennox MERIT ML193UH Installation Instructions Manual page 20

TYPICAL AIR INTAKE PIPE CONNECTIONS IN UPFLOW DIRECT VENT APPLICATIONS
Pipe size determined in table 5
2"
or 3"
TRANSITION
2"
*2"
AIR INTAKE
2"
2"
2"
or
* When transitioning up in pipe size, use the shortest length of 2" PVC pipe possible.
NOTE − Intake and exhaust pipe must be the same diameter.
FIGURE 26
TYPICAL AIR INTAKE PIPE CONNECTIONS IN HORIZONTAL DIRECT VENT APPLICATIONS
(RIGHT HAND DISCHARGE SHOWN)
3"
2"
2"
TRANSITION
or
*2"
2"
2"
2"
*2"
AIR INTAKE
* When transitioning up in pipe size, use the shortest length of 2" PVC pipe possible.
NOTE − Intake and exhaust pipe must be the same diameter.
FIGURE 27
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