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Why is my furnace leaking water?

Updated: Dec 22, 2022

why is furnace leaking water

So your Furnace is Leaking Water When the Heat Is On?

Heating is important for ensuring the comfort of a home. As a result, interested individuals should monitor their heating system for signs of serious issues that should be checked out by a heating professional sooner rather than later.

One excellent example of such issues would be a furnace leaking water when the heat is on, which could become something worse unless it is acted upon.

What Are Some Potential Causes?

Here are some of the most common causes of furnaces leaking water when the heat is on:

  • Condensing Drain Has a Problem

Some people have condensing furnaces, which are high-efficiency furnaces with a second heat exchanger that can extract extra heat from the water vapor vented out in the normal course of things.

If interested individuals are unsure, they can check the material of the vent. This is useful because condensing furnaces have PVC vents while other furnaces have metal vents.

In any case, a condensing furnace might be leaking water because there is a problem with the condensing drain contained therein.

  • Condensate Pump Has a Problem

Generally speaking, condensing furnaces drain downwards. However, there are some setups in which the water vapor has to go upwards and outwards. Something that is made possible by the presence of a condensate pump.

Water vapor can't be pumped out when the pump has suffered a serious issue, thus resulting in an eventual leak.

  • Humidifier Has a Problem

Not every furnace has a humidifier.

However, those that do are very likely suffering from a humidifier-related problem when they experience a leak.

Unfortunately, there is a wide range of potential causes for said issue. For example, the pad might have become hard and crusty because of mineral build-up, thus making it incapable of absorbing water.

Likewise, the drain might have gotten clogged, meaning that it will need to be cleaned out before it can return to proper functioning.

  • Cracked Heat Exchanger

The heat exchanger is one of the most important components of a furnace. Thanks to this, heat exchanger-related issues are some of the biggest furnace problems.

For instance, a heat exchanger can crack, which in turn, can let out moisture as well as carbon monoxide. This is something that interested individuals should never attempt to handle on their own.

Instead, they should turn off their furnace before calling in heating professionals for a full list of options, which are very likely to boil down to getting a replacement for their broken furnace.

Experiencing furnace problems?

The best solution is to contact reliable and reputable heating professionals such as those with Deluxe Plumbing and Heating, who can handle a wide range of issues with a wide range of furnaces.


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