When you step in a puddle of water near a furnace, it’s natural to be concerned. This is the more obvious sign that there is a water lead somewhere that needs to be identified and fixed. There are a number of possible causes, some need professional intervention, and some you can fix yourself with no special skills or tools. In this article, we will show you how to troubleshoot the problem and get it fixed quickly.

What Type of Furnace Do You Own?

Before you can find and fix the problem, you need to know more about the type of furnace you have in your home. There are two main types of furnaces in common use: conventional and high-efficiency models. They share a lot of characteristics, but they are different if you know what to look for. Here are three ways that you can determine which type of furnace you have:

1.    The Annual Fuel Utilization Efficiency (AFUE) Rating

The AFUE rating should be easy to find, it’s typically printed on the yellow EnergyGuide label on or near the furnace. When you find the label take a look at the numbers. A conventional furnace will have an 80% AFUE rating which means that 80% of the energy used is converted into heat and 20% is wasted via exhaustion, air leaks, and openings. In comparison, a high-efficiency furnace will have an AFUE of 90% or more.

2.   The Furnace Exhaust Pipe

This is probably the most obvious difference between a conventional and high-efficiency furnace. An exhaust pipe is also known as a flue pipe and its purpose is to vent the exhaust gasses from the furnace out of the home. If the flue pipe is metal, it’s likely that you have a conventional furnace installed in your home. If the exhaust pipe is white PVC (polyvinyl chloride) plastic then you have a high-efficiency furnace.

3.   The Age of Your Home

Older homes tend to have conventional furnaces unless extensive updates have been made in the last decade. New construction homes and those with updated or replaced HVAC systems usually have high-efficiency furnaces installed.

Dealing with a Furnace Water Leak

Now that you know what type of furnace you have it’s time to troubleshoot and fix the problem. Let’s look at the approach you should take for conventional and high-efficiency furnaces:

Conventional Furnaces Water Leaks

When water leaks from a conventional furnace, this usually means that there is a malfunction in either the exhaust pipe or the built-in humidifier. The humidifier removes excess water from the furnace drain line which can become cracked or clogged. A buildup of water will ultimately lead to a release of water from the humidifier back into the furnace and onto the floor. To most people, it will look like the water is leaking from furnace components, but the humidifier is the source of the leak.

The next step is to inspect the humidifier water lines for any pinhole leaks or larger cracks. If the lines look good, check where they fit into the humidifier to ensure that they are secure. A poorly filled drain line is a common source of furnace water leaks.

If the humidifier and drain lines are in good shape, it’s time to turn your attention to the exhaust pipe.

Before you work near the pipe, it’s important to understand that it can be extremely hot and it should not be touched with bare skin. Always wear gloves and if you’re unsure about working with the flue pipe contact a local HVAC specialist. If you’re confident, check if the pipe is badly fired or loose because water can leak from this area. In some cases, it may be easy to push the exhaust flue back into position.

High-Efficiency Furnaces Water Leaks

In a high-efficiency furnace, a pair of heat exchangers absorb a lot of heat and the gas that’s expelled via the exhaust flue is turned into liquid. This creates condensation which is removed from the system by a condensate drain. The condensate drain and connected lines can become clogged with dust, dirt, and other particulates. If this happens, the water has nowhere to go and it will back up and spill onto the floor.

To fix the problem, it will be necessary to clean and flush the condensate drain and drain lines to get the water draining again. In many cases this will be simple, pour an equal ratio of white vinegar and hot (not boiling) water in the drain line. The process can be repeated several times and any small clogs should be flushed clear.

The useful lifespan of a condensate pump is 3-5 years and past this point, it’s not likely to perform at optimal efficiency. The pump pushes the condensate out of the furnace and into the drain line. Even if the drain lines are clear there may still be a water leak if the condensate pump is failing or it has failed entirely. This is an inexpensive part, but you will need to contact a local HVAC specialist to install it for you.

Furnace Problems: Repair or Replace?

As you can see, many of the causes of water leaks are minor issues that can be repaired easily. For this reason, we recommend an annual furnace inspection before the start of each heating season. This gives an HVAC technician the opportunity to clean the furnace and make adjustments to improve the performance and energy efficiency. During this inspection, a water leak can be identified and repaired quickly. But, like any piece of complex equipment a furnace has a finite lifespan, and if you have frequent problems it may be time to consider an upgrade. Let’s take a look at four things that are a warning sign that a furnace is reaching the end of its lifespan:

  • Frequent repair bills,
  • Rising energy bills.
  • The furnace is making strange noises.
  • The equipment is 16 years old or older.

If you need a furnace repair or upgrade, contact your local HVAC specialist.