Furnaces do leak water at the base and you may also find that the filter is wet. There are a number of reasons that may cause this, but the most common one is a condensation leak. Inasmuch as leaks may not interfere with the normal operation of your furnace, they can increase its inefficiency which ultimately leads to high utility bills and costly repairs down the road.
Homes with high-efficiency furnaces, that is, furnaces with AFUE (annual fuel utilization efficiency) rating of 90% and beyond may experience condensation. If you are not sure whether your system is a high energy efficiency unit, you can just check its vent pipe. High energy efficiency furnaces usually have white plastic vent pipes.
In a typical high energy gas furnace system, condensation is usually channeled to a floor drain. The leak you are seeing could be as a result of clogged condensation tubing or breaks in the line.
Standard efficiency furnaces have metal exhaust piping and ordinarily should not have condensation. In case you have this type of furnace and you are experiencing a water leak problem, the flue pipe may be incorrectly sized. Where this is the case, hot exhaust tends to cool down and condense within the pipe and thereafter draining back to the furnace and leaking out.
A Faulty Secondary Heat Exchanger
If furnace condensation is not the problem, then chances are the secondary heat exchanger of the furnace is faulty and as a result, causing water to leak at the base of your furnace. This is a much more complicated problem and is usually expensive in fixing. In some instances, you may even have to replace the entire furnace system.
A Leaky Furnace Humidifier
If your furnace humidifier is leaking within the unit, it can cause water to accumulate at the base of your furnace. It is important you have an annual HVAC service check because during such procedures the technicians usually go through a checklist and inspect every component including the humidifier within your system. Problems such as leaking furnace humidifiers can be spotted in good time and rectified.
If you can, kindly call for a tune-up because this problem will not just cause inconveniences with the pooling of water around your furnace, but can also damage a lot of internal components within your furnace system.
Clogged Internal Drain System
This is another cause of leaks at the base of furnaces which has been reported by a good number of homeowners. If your AC unit is still in operation and it happens to share an internal drain with your furnace system, an internal drain system plug may be responsible for sending water to the furnace.
If you experience this problem, it is important that you call for professional help because it may be too technical for you even if you are a DIY enthusiast.
Furnace leaks can cause a whole lot of problems including damaged internal parts, mold growth, and even flooring and wall damages. Getting the help of a reputable HVAC specialist should solve the problem.