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There’s Water around My Furnace… What’s Going On?

large-furnaceMost people have a basic idea about how gas furnaces operate: a pilot light or electronic ignition system lights gas burners, which generate the heat that warms up the air sent into the house. This process doesn’t sound like it involves water at any point. So when a homeowner notices that there is water coming out the base of a furnace, it seems strange.

This does happen with furnaces, and if you see it occurring with yours, you almost certainly need professional heating repair in Plattsburgh, NY or elsewhere in Northeast New York or Northwest Vermont. A number of problems might be at work, ranging from minor malfunctions to the need to replace the entire furnace. But no matter what, you must have trained technicians on the job: a gas furnace is potentially dangerous if someone without licensing and training tries to work on one.

Do You Have a High-Efficiency Condensing Furnace?

This is a topic we recently discussed on the blog: furnaces that are achieving high levels of energy efficiency thanks to using a second heat exchanger. These are called condensing furnaces, and they can start to leak water under certain conditions.

The second heat exchanger in a condensing furnace is where the actual “condensing” occurs. The exhaust vapor left over in the heat exchanger moves to the second heat exchanger, where condensing the vapor draws out even more thermal energy. This creates water, which flows from the exchanger through a tube down into a drain. This water can escape through leaks in the tube or overflow because the drain has become clogged.

There is also the chance the second heat exchanger is cracked, allowing the water to simply run out. This is major repair and often it’s less expensive to have the furnace replaced.

Other Possible Problems with the Furnace

Standard furnaces that only have a single heat exchanger can also encounter problems with water condensation. The exhaust vapor from the heat exchanger goes directly through a flue to the outside of the house. If the flue contains blockage, or it was incorrectly sized for the furnace, the exhaust vapor will condense inside the flue, then drip down until it runs out onto the floor. The flue will need to be cleaned or else a larger flue chimney put in.

It Might Not Be the Furnace at All

If you’ve already run your air conditioner this season, the water you’re seeing might be coming from the condensate pan on the AC as it overflows and falls down on the furnace unit (which is usually installed below the air conditioner). This is a problem for both the AC and the furnace, since water dripping on the furnace will promote corrosion that can ruin the system. If you use whole-house humidifier, a malfunction in it can also lead to water falling onto the furnace.

The important part of all this is that water around a furnace isn’t normal and means there is something wrong with part of the HVAC system. Don’t try to diagnose this issue on your own: that’s why you have us around! We’re experienced with all types of heating and air conditioning systems, and we’ll find the source of the trouble and have it repaired.

Red Rock Mechanical LLC has served Burlington, VT and the Plattsburgh, NY area for more than 23 years.

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