The evaporator coil has flooded the pan and secondary pan. I have had two estimates with totally different results. One claims I need a new coil, plenum, and all new ductwork ($2300). The second said that the hole in the coil could be repaired, and no replacement (just upgrade to tpc valve) is needed. Is it necessary to replace the ductwork, if a like evaporator is put in? How much should I be expecting to pay for a replacement? The coil is installed horizontally. The outside unit was replaced three years ago. Any help appreciated.
Stephen, Houston, TX
There are many other things that could lead to the water overflow problem, ranging from simple to complex, besides a hole in the evaporator coil. The most simple is a drain line that’s clogged and has caused the condensation to build up and overflow the main pan and the secondary pan which could be remedied by a cleaning. Sometimes the drain line should be replaced to ensure proper slope to drain. Drain line service is part of the routine system maintenance that we recommend. There could be holes or cracks in the main drain pan which would allow an overflow. This would require replacement of the drain pan and often the whole coil, depending on the construction of the coil/pan assembly. Today’s coils are taller than older coils, often requiring duct plenum modification to allow it to function properly in the existing air conditioning system. Another possibility is that the system could be freezing up and then thawing out, releasing a large amount of water. This happens often in mild or cooler weather when there is a need to cool the space when it is cool outdoors. Freeze-ups also can occur due to low refrigerant or low airflow in the system. Sometimes a coil can be dirty causing improper drainage, since water is blown into the ductwork and then drips out uncontrolled. Except in the case of a freeze up or water blowing off the coil, the secondary drain should catch the water and either hold it and shut the system down, or allow it to drain off. There are accessory switches available to help stop this. To address the issue of replacement or repair of your evaporator coil, the first question would be how old is the coil. If the evaporator coil exceeds seven years on average then a repair to the evaporator coil could lead to additional leaks and cause the same reoccurring issue. I would not recommend ANY repairs to an older evaporator coil! I noticed that the coil is installed in a horizontal position so it is important to find out how much damage was done to the existing plenum. As the coil leaked the refrigerant downward it would have caused excessive moisture on the evaporator coil until it actually started to “freeze.” This results in higher statics on the blower and it most likely was blowing condensation off the coil and into the insulation on the coil cabinet and plenum. This will be a concern with the wet insulation in the cabinet and can cause condensation to form on the outside bottom of the unit until it dries out totally. Since we are just starting the cooling season it could take all season before there would be enough down time or heating time to properly dry the cabinet insulation. Regarding replacement of the complete ductwork system, I would have to visually inspect it to evaluate its condition. You are wise to always get more than one estimate on repairs. ARS/Rescue Rooter offers FREE second opinions on any repair/replacement services. Replacement of the evaporator coil and plenum (if it had become saturated), would be a possible repair but the cost could possibly exceed half the investment of a replacement air handler. I suggest also getting an estimate on complete air handler replacement. Then compare that estimate with the repair estimate to make an informed decision. Keep in mind that the repair would most likely have only a one year parts warranty and, depending on the servicing company, very little labor warranty. A replacement air handler would come with a five year parts warranty and at the least a one year labor warranty. Efficiency should be a major factor in your final decision. Even though your outdoor AC unit is only three years of age, complete system replacement with new high efficiency equipment could result in greater savings on your power bills. When you are looking at an expensive repair, it makes sense to consider all the options. I suggest you contact the ARS/Rescue Rooter branch in Houston, TX at (713/281/832) 777-7777 for a professional inspection and free estimate on repairs or possibly total replacement of your air conditioning system. They will also advise you on regular AC tune-ups that can help prevent problems in the future.