Hansberger Refrigeration Blog: Your AC Repair Resource

3 Signs Your A/C Drain Line is Clogged

A clogged A/C drain pipe may not be obvious at first, but it won’t be a secret long. Your central air conditioner generates many gallons of condensate every day as it extracts water vapor from the air as part of the cooling function. As long as everything goes according to plan, this process happens without incident.  Condensation from the evaporator coil accumulates in the drip pan beneath the indoor air handler, and is then carried away through the drain pipe.

However, if a clogged A/C drain pipe occurs, things start going wrong very quickly.  Here are three signs to be aware of:

1. Pooling water.

A totally clogged drain line will rapidly cause drip pan overflow. Every time the system cycles on, more condensate is added and the overflow continues. Water spreads across the floor surrounding the air handler. Since the unit’s typically installed inside an HVAC closet or other enclosed space, however, some time may elapse before occupants of the house become aware of it. By then, serious water damage may have occurred.

2. Mold contamination.

Maybe the drain line’s only partially clogged and drains slowly. Overflows from the drip pan may be less conspicuous. However, water leakage concealed beneath the air handler may trigger toxic mold growth as well as rot the floor structure. If you notice a musty smell near the air handler that doesn’t go away, suspect mold contamination underneath the unit caused by a sluggish drain pipe and intermittent overflows.

3. System shutdown.

Some air conditioners are fitted with a drip pan sensor that shuts off power to the unit to prevent overflow when the pan is filled. If you attempt to start the air conditioner and it promptly shuts off again, a a clogged A/C drain pipe may be the reason.

Service by a qualified HVAC technician includes clearing the drain line clog plus adding biocide tablets to the drip pan to prevent mold recurrence throughout the cooling season.

For professional service to resolve a clogged A/C drain pipe, contact Hansberger Refrigeration and Electric Company.