Troubleshooting Tips for Common Condensate Drain Problems in Central A/Cs – Sobieski Services | DE, NJ, PA, MD

Troubleshooting Tips for Common Condensate Drain Problems in Central A/Cs

It’s no wonder A/C condensate drain problems happen so often. The average four-ton central air conditioner produces more than 20 gallons of liquid condensate daily—more if the humidity is high, as is often the case in our coastal climate. Water condensed at the evaporator coil is continuously channeled down into the condensate drip pan, then flows through a drain line into the household sewer or a discharge point outdoors. It all happens in the confines of the indoor air handler, often tucked away in a secluded part of the house that receives little notice. By the time condensate drain problems are discovered, substantial water damage may have occurred.

Condensate drain problems require qualified HVAC service to access the air handler and trace the problem through the drain system. It’s not a do-it-yourself procedure. However, you can troubleshoot a couple of common scenarios yourself so you’ll have an idea of what the technician may diagnose.


When blockage occurs in both condensate drain lines, it’s often indicative of extensive algae growth inside the drain pan. An overflowing pan first manifests itself as dripping and pooling of water around the air handler. An HVAC technician will clear the blockage, drain and disinfect the pan and install time-release biocide tablets to inhibit algae formation. He may also suggest installing a safety float switch that automatically shuts down the unit if the pan reaches overflow stage.

Coil Icing

When the evaporator coil runs too cold, condensate freezes instead of flowing down into the drain pan. The growing block of coil ice expands outward beyond the extent of the drain pan underneath. When the system shuts off and ice rapidly melts, water drips directly onto the floor, damaging building materials. Resolving coil icing problems involves troubleshooting common causes such as insufficient airflow and low refrigerant levels.

At Sobieski Services, Inc., our goal is to help our customers in Delaware, Pennsylvania, Maryland and New Jersey learn more about energy and home comfort issues – especially HVAC and plumbing issues – so that they can save money and live in healthier, more comfortable homes.

Photo Credit: Photos by Mavis via Compfight cc

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