One of the most common reasons for a homeowner to call an air conditioning service technician is when the condensate drain line has clogged. In most cases this is a huge waste of money. The fix is often simple and special tools are not required. To make this type of service call worse, a backed-up condensate drain line is an avoidable problem. Simple maintenance, peformed twice a year, keeps even the most used air conditioning condensate drain line from getting a clog.
Over time, sludge forms in an air conditioner's drain line. This happens because the normal current from condensate is not enough to flush the line. Tiny sludge particles form along the bottom of the long horizontal part of the drain line. Once in a while, some sludge will break free and travel to a restriction, where it settles. Once enough sludge particles collect in one spot, a clog is created. Then the water will back up into the air conditioning drain pan. After the pan is full, water overflows into the furnace. This is when most homeowners notice the problem.
Cleaning an Air Conditioner's Condensate Drain
Turn the air conditioner off at the thermostat. Take the panel off the part of the inside air conditioning unit where the evaporator coil is. Two copper lines and the condensate drain line connect to the evaporator coil. Inspect the drain pan. If the drain is blocked, the pan will be full of water. Suck the debris from the drain pan with a wet/dry vacuum, using care to avoid damaging the coil's fins. Place a rag over the spot where the drain line enters the pan. This will help keep the mess to a minimum.
Find where the condensate pipe exits the house, usually located near the copper lines that connect to the outside air conditioning unit. Follow the copper lines back toward the house. Look for a plastic pipe. It is usually a 3/4 inch plastic pipe (black, grey or white in color). If the drain pipe does not terminate above the ground, dig a small hole in the soil near the spot where the copper lines enter the house and look for the condensate drain pipe. Follow the unearthed section of pipe until it exits the soil. If the pipe stops underground, then this is the problem. Clean the dirt out of the end of the pipe, add a 90-degree fitting and a short piece of pipe to get the end of the end of the drain line out of the ground. If the condensate line does not exit the house with the copper refrigerant lines, you must walk around the house to find it. Look for a plastic pipe that sticks out of the ground for no apparent reason or a wet patch of dirt.
There should be a 90-degree fitting connected to the end of the condensate drain line. The 90-degree fitting prevents dirt from falling into the exposed end of the pipe. This fitting should not be glued on. Remove the fitting. Often this is the place where the clog forms. If so, removing the elbow releases the restriction and the sludge will flow freely. Use a wet/dry vacuum to stuck the sludge from the pipe. In most cases, this will completely free the drain. For extreme cases a hose will be needed. This is why you put a rag in the drain pan. Turn the water hose on. Fold the hose near the drain line to stop the water. Place the end of the hose against the end of the condensate line. Release the water for ONLY ONE SECOND. Allow the water to exit the pipe. The clog should break free. If not, repeat this step. Go inside, remove the rag and add water to the drain pan. Water should flow freely to the outside. When the blockage is free, reinstall the front panel of the inside unit and the elbow on the drain line outside.
Air Conditioning Condensate Drain Line Maintenance
Air conditioning condensate drain lines should have maintenance perform at least once per year, twice is better. This is a simple process. Squeeze a couple drops of dish soap into the drain system, then pour 1/2 to 1 gallon of warm water into the drain pan. Many air conditioning systems have a Tee-fitting in the drain line near the air handler. If so, open the top of the T-fitting and slowly pour the soap and water down the drain. If your system does not have the T-fitting, then you must remove the evaporator coil's cover to access the drain pan. Pour the water into the pan.
Air conditioning technicians love clogged condensate drain lines. It is an easy service call and the profit margin is very high. With simple maintenance you can avoid this problem all together. You will not need to call them until there is a real problem.