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.
Ecaporator Coil Using a Common Drain
Figure 46
Condensate Trap with Optional Overflow Switch
Figure 47
507582-02
CAUTION
Issue 1621
Page 33 of 59