Lennox A97UH2E Installation Instructions Manual page 35

*Piping from furnace must slope down a minimum of 1/4" per ft.
toward trap.
Figure 53. Condensate Trap Locations
(Unit shown in upflow position with remote trap)
Figure 54. Unit with Evaporator Coil
IMPORTANT
When combining the furnace and evaporator coil
drains together, the A/C condensate drain outlet must
be vented to relieve pressure in order for the furnace
pressure switch to operate properly.
508390-01 Issue 2327 Page 35 of 60