Condensate Drain Line Woes


A seemingly more common service call we respond to is what we refer to as the Clogged Condensate Drain Line. A condensate drain line is a gravity fed pipe that carefully and safely removes the condensation buildup from the evaporator coil inside the air handler. On a normal summer day, an air conditioning system can remove anywhere from 5 to 20 gallons of condensate from the air. This cool water fills the evaporator drain pan, and then flows out of the system through piping to the exterior of the home.

The pipes that the water flows through as well as the drain pan itself are susceptible to algae or other organic growth. During a preventative maintenance, these pipes are vacuumed or blown out to aid in the removal of this debris. The drain lines are also treated with an anti-microbial treatment such as vinegar or bleach, depending on the severity of the debris found. We also recommend treating the drain lines on a regular basis, especially during the warm and humid months in Florida.

One issue that can arise can be seen in the photos below. This drain line was vacuumed several times with water poured through during the vacuum. We also blew high velocity nitrogen through the line to purge any debris that was left behind. Even after providing all of the standard treatment methods, the line still clogged a week later. We cut the line open and what we found was astounding.

Clogged Drainline trio
First Photo: Freshly Cut After Using Nitrogen    |     Second Photo: Four Days Old     |     Third Photo: Eight Days Old

What we realized was that when the air conditioner was not operating and producing condensation, the debris was dehydrating. It was creating a long string of dried debris. We could vacuum and use nitrogen but either way, the air would only pass by the dried mass. Then when condensation was introduced, the debris would reconstitute and begin growing again, thus restricting proper water flow.

Then the water builds up, and trips the safety float switch, which disconnects control voltage from the thermostat and shuts the air conditioner down. Our technicians are then called and respond to a “non functioning” air conditioner, but in reality the air conditioner is functioning correctly. It is the drain line that is in need of service.

This is why there are many drain line issues after the winter months, because the indoor unit does not produce condensation at this time. If a system doesn’t produce condensation, the line dries out, and debris solidifies.

Debris Blown Out Of Drain Line With Nitrogen

Whatever the condition of the drain line, we have many tools in our tool bag to get almost any issue corrected.

Vicky, T.M.G.

Beacon Services & Appliances | Beacon Air & Heat, Inc

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