From evaporator coil
Optional
overflow switch
Figure 50. Condensate Trap with Optional Overflow
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.
(Trap at coil is optional)
Drain pan
31-5000728 Rev. 0
Field provided vent
(1" min. 2" max. above
condensate drain)
Furnace condensate
drain connection
Switch
(Unit shown in horizontal left-hand discharge position)
Evaporator coil
Piping from furnace and evaporator coil must slope down a minimum 1/4" per ft. toward trap
Figure 52. Evaporator Coil Using a Common Drain
(Trap at coil is optional)
Field provided vent
(1" min. 2" max. above
condensate drain connection)
Condensate
drain connection
Figure 51. Evaporator Coil Using a Common Drain
4"min
5"max
5' max.
PVC pipe only
Page 43
Evaporator drain
line required
Field provided vent
(4" min. 5" max. above
condensate drain
connection)