The Furnace Condensate Line Is Leaking

Pipe Problems

• One of the most common types of condensate line issues is with the pipes. Condensate pipes must channel water under rough conditions. They cannot let air into the system without impairing efficiency. The water they carry is often highly corrosive, and they must perform in all temperatures and types of weather. Over time the pipes can crack and create leaks. They must be replaced.

Cracks in the Pan

• The condensate pan is an area where moisture collects and runs down the condensate line into the drain. The pan can be a source of leaking, especially if it cracks or is damaged. In this case, the water will leak out of the pan instead of entering the drainage line; making it difficult to pinpoint the problem.

Over-running Pans

• Condensate lines use what is known as a trap system, or a section of piping that allows water to escape but keeps air from entering -- it's not unlike the curved pipe under a sink, the "P-trap." The trap seal cannot be too deep or it could seal off air flow too well, become clogged and create pressure issues. This leads to water backing up through the condensate pan and eventually overflowing the pan itself. If the pan is overflowing, check the U-shaped trap installation first to see if it is the problem.

Drain Overflow

• If the leak is occurring at the bottom of the condensate line, check the drain itself for problems. Drains in concrete or through the walls can become clogged with sediment and debris. Eventually they will overflow and leak water across the floor. In this case the line is working correctly but the drain needs to be cleaned out to prevent problems.