The largest of my three central air units in the attic has two drip condensation pipes coming out of the evaporator coil box (not one that had an overflow opening that drips into the overflow pan). It has two drip lines coming out of the unit. One goes to the standard pvc drain that goes to a bathroom drain. The second drip pipe goes directly to the overflow drip pan and drains out to the eave of my house.
This year (after 10 years of use), the 2nd drip pipe (the one that goes directly to the overflow pan) is getting used and there is a constant drip out the front of the house from that emergency overflow pan.
Why is that 2nd drip line from the A/C getting used this year? Thanks.