Equipment
- Carrier gas furnace with cooling coil in the attic
- Primary and emergency condensate drain lines ending under the carport
Clogged condensate drain on a Carrier attic furnace in San Mateo
Problem: In this San Mateo home the Carrier furnace and cooling coil sit in the attic, and the condensate lines end at two small outlets under the carport roof. The owner noticed one of them dripping heavily, on and off, and had the right questions ready: is that the primary line or the emergency line, and is the primary partly clogged?
Diagnostics: A system like this pulls a lot of water out of the air when it cools, and it has two ways to get rid of it. The primary line handles it in normal operation. The emergency line is the backup, and it usually ends somewhere you’ll see it, so water coming out of it tells you the primary needs attention. Our technician went up into the attic, went over the equipment and both drain lines, and checked the outside ends. The primary condensate line was clogged and restricted.
Solution: We cleared the primary line from both ends, at the evaporator coil in the attic and at the outside termination, using suction and pressure to pull out and push through the buildup. The emergency line was cleaned as well, as preventive maintenance. Then we checked both outlets under the carport and confirmed the water was draining.
Result: Both lines were clear and draining at the end of the visit, and the system was running properly. The owner also has an answer to the question that started it all, which line was which.
If your furnace is in the attic, it’s worth knowing where the emergency drain comes out. Water there is the system asking for attention, and a clogged line is a lot easier to deal with than a stain on the ceiling below.
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