Introduction – Why Is My Furnace Leaking Water
A furnace leaking water can be a very serious issue. It can cause water to pool around the furnace and potentially cause damage to the flooring and surrounding walls. It can also create a musty smell and cause mold to grow in the area. Additionally, the leaking water can cause the furnace to become less efficient, costing more to run and potentially leading to further damage. It could be time to replace the old furnace or if its a warranty covered defect then diagnosing the problem is paramount.
If your furnace is leaking water, it is important to address the issue as soon as possible to prevent damage to the furnace and your home. You should contact a qualified heating and cooling technician to diagnose the problem and recommend a course of action.
Symptoms Of A Leaky Furnace
Many furnace types can leak water. However, you should be aware that high efficiency furnaces are one of the major reasons behind water leaks. The reason is that the high efficiency furnaces generate a lot of water vapor which lends itself to leak problems if there’s a problem with the plumbing. Let’s take a look at what are symptoms of a leaky furnace.
Exhaust Pipe Leak
You might notice directly that water is dropping from your furnace. The exhaust pipe that comes out of the furnace will be angled upward and out of the house. When the hot exhaust air hits the pipe there will be condensation. This is usually collected by the collector. Problems like cracks, or even worse the exhaust pipe being pitched incorrectly will lead to condensate dripping out or pooling in the pipe instead of running into the drain. It indicates a problem. For now it’s just a leak – but whether the cracks let exhaust escape or the pooling of the water leads to water logged components later – you should get it checked out asap.
Water Pooling Around Furnace
Another symptom is that you can’t see a leak, but you notice water by the furnace or all around the furnace. It could be a wet patch, or a pool of water. It could be water thats under the furnace. Sometimes there’s a musty smell accompanying the leak. Because most of the problems we list below will happen when the furnace is in operation, you should expect water to leak or show up when the heat is on.
Furnace Making Unusual Noises
An unusual noise from your furnace might indicate a problem. A leak inside the furnace can cause components to work harder or differently than usual, and this can cause changes in the sounds your furnace makes. These noises can range from subtle to quite loud, and might include rattling, banging, squeaking, or whistling noises. Confused? A gurgling or bubbling sound, for instance, may suggest that water is not draining properly due to a blockage in the condensate drain line. On the other hand, a high-pitched whistling sound could indicate that water is leaking onto a hot surface inside the furnace and evaporating.
Can A Furnace Leak Water? Yes It Can
There are several potential reasons why a furnace might leak water. Many of the reasons concern how condensate is drawn out of the furnace. Condensate forms when a cold surface comes in contact with moisture in the air. The cold surface induces the moisture to condense, forming tiny droplets of liquid water. With that in mind, here are some of the most common causes include the following. Take a look at the picture of one type of furnace below and see the caption for two of the four reasons why there’s a water leak.
1. Clogged Condensate Drain Line
A condensate drain line is a pipe or tube that is used to carry water away from a furnace. The furnace produces condensate (water) as a byproduct of the combustion process, and this water needs to be drained away from the furnace to prevent it from accumulating and causing damage.
The condensate drain line is typically located near the furnace and is connected to the condensate pump, which uses a small electric motor to move the water through the drain line and into a drain or sewer. The condensate drain line is an important component of the furnace, as it prevents the water from accumulating in the furnace and causing damage.
If the condensate drain line becomes clogged or obstructed, or its graded incorrectly, it can prevent the water from being drained away from the furnace, which can cause the water to accumulate and leak out of the furnace. It is important to maintain and clear the condensate drain line to ensure that it is functioning properly and preventing water from accumulating in the furnace.
2. Malfunctioning Condensate Pump
A condensate pump is a device that is used to remove water from a furnace. The furnace produces condensate (water) as a byproduct of the combustion process, and this water needs to be drained away from the furnace to prevent it from accumulating and causing damage.
The condensate pump is typically located near the furnace and is connected to the condensate drain line, which carries the water away from the furnace and into a drain or sewer. The pump uses a small electric motor to move the water through the drain line and prevent it from accumulating in the furnace.
In some cases, the condensate pump may be integrated into the furnace itself, while in other cases it may be a separate device that is attached to the furnace. Regardless of its location, the condensate pump plays a critical role in the operation of the furnace and is essential for removing the water that is produced during the combustion process.
If the condensate pump malfunctions or fails, it can cause the water to accumulate in the furnace and leak out, potentially causing water damage and reducing the furnace’s efficiency. It is important to maintain and repair the condensate pump to ensure that it is functioning properly and preventing water from accumulating in the furnace.
3. Cracked Heat Exchanger
A cracked heat exchanger can cause a furnace to leak water for several reasons. The heat exchanger is a component of the furnace that is responsible for transferring heat from the combustion process to the air that is circulated throughout the home. As the furnace produces condensate (water) as a byproduct of the combustion process, the heat exchanger is in contact with this water.
If the heat exchanger develops a crack, it can allow the water to leak out of the furnace and into the surrounding area, potentially causing water damage. In addition to causing water damage, a cracked heat exchanger can also reduce the furnace’s ability to transfer heat, which can reduce its efficiency and cause it to use more energy to produce the same amount of heat.
A cracked heat exchanger can also create a safety hazard, as it can allow dangerous gases, such as carbon monoxide, to leak out of the furnace and into the home. It is important to repair or replace a cracked heat exchanger to prevent water leaks and other potential hazards.
4. Malfunctioning Humidifier
A furnace humidifier is a device that is attached to a furnace and is used to add moisture to the air that is circulated throughout the home. The furnace humidifier uses water to produce a fine mist of moisture that is mixed with the warm air from the furnace as it is distributed throughout the home.
Overall, a furnace humidifier is a valuable device that can help to improve the air quality and comfort of your home, and can provide a number of benefits for your health and your belongings.
In addition to providing health benefits, a furnace humidifier can also help to reduce static electricity, prevent furniture and woodwork from drying out and cracking, and reduce the risk of damage to musical instruments and other delicate items.
If the furnace is equipped with a humidifier, it will add moisture to the air that is circulated throughout the home. If the humidifier malfunctions or is not properly maintained, it can cause water to leak out of the furnace.
5. Cracked Exhaust Pipe Or Incorrectly Pitched Exhaust Pipe
If the exhaust pipe of a high efficiency furnace is cracked, the furnace will become less efficient and the exhaust gases will be released into the home instead of being vented to the outside. This can be dangerous as the exhaust gases contain carbon monoxide which is poisonous. It is important to have any cracks in the exhaust pipe repaired immediately to ensure the safety of the home. Similarly cracks can cause water to leak and lead to water damage, mold, and other structural damage. It is important to have any cracks in the condensate pipe repaired immediately to prevent further damage.
As we mentioned above, an incorrect pitched exhaust pipe will lead to condensate improperly pooling because it will condense and fall to the lowest point which is in the middle somewhere due to the incorrect pitch. This could lead to a leak or worse, damage to the furnace.
How To Diagnose A Water Leak In Your Furnace
To diagnose a water leak in a furnace, you will need to perform the following steps:
- Locate the source of the leak: The first step in diagnosing a water leak in a furnace is to determine where the leak is coming from. The most common sources of leaks are the condensate drain line, the condensate pump, the heat exchanger, and the humidifier. It might be hard to see the leak or you might be mislead by where the leak is. You will see a puddle of water but the leak is too slow to observe. Look at the pipes that come out of the furnace and look for moisture or even a single droplet that’s dangling from a pipe.
- Check the condensate drain line: If the furnace has a condensate drain line, check to see if it is clogged or obstructed in any way. A clogged drain line can cause water to leak out of the furnace. It’s also possible that the grade of the line is not correct which causes condensate to leak back into the house rather than out.
- Inspect the condensate pump: If the furnace has a condensate pump, check to see if it is functioning properly. A malfunctioning or failed pump can cause water to leak out of the furnace. It may be hard to check whether the pump is working. Outside of the furnace the pump may have its own power source and you can hear it in operation. In order to truly see if the pump is working, you’ll need to look inside.
- Examine the heat exchanger: If the furnace has a heat exchanger, inspect it for cracks or other damage. A cracked heat exchanger can cause water to leak out of the furnace and into the home.
- Check the furnace humidifier: If the furnace has a humidifier, make sure it is properly maintained and functioning properly. A malfunctioning humidifier can cause water to leak out of the furnace.
If you are unable to diagnose the problem yourself, or if you are unsure how to proceed, it is recommended that you contact a qualified heating and cooling technician to diagnose
What To Do If Furnace Is Leaking Water
It’s highly unlikely that if you’re untrained that you’ll be able to fix this problem yourself. However, to give you a sense of what needs to be done, let’s take a look at potential ways to address each of these problems.
To fix a furnace that is leaking water, you will need to perform the following steps:
- Locate the source of the leak: Yes, you will still need to take the first step in determining where the leak is coming from. The most common sources of leaks are the condensate drain line, the condensate pump, the heat exchanger, and the humidifier.
- Clear the condensate drain line: If the furnace has a clogged or obstructed condensate drain line, it will need to be cleared to allow the water to drain away from the furnace. This can typically be done using a wet/dry vacuum or a special condensate pump that is designed to clear clogs. If it’s a more serious problem like an incorrect grade, you will have to take out the pipe and reinstall it.
- Repair or replace the condensate pump: If the furnace has a malfunctioning or failed condensate pump, it will need to be repaired or replaced to restore its ability to drain the water away from the furnace. Hooking up a new pump and then testing that it works will not be easy and is highly technical. We suggest getting a technician who is trained in your particular brand!
- Replace the heat exchanger: If the furnace has a cracked heat exchanger, it will need to be replaced to prevent water from leaking out of the furnace and into the home.
- Repair or replace the humidifier: If the furnace has a malfunctioning humidifier, it will need to be repaired or replaced to prevent it from causing water to leak out of the furnace.
How Much Condensate Does A Furnace Produce?
The amount of condensate produced by a furnace depends on several factors, such as the efficiency of the furnace, the temperature of the air coming through the furnace, and the size and type of fuel used. Natural gas, high efficiency furnaces are notorious for generating a lot of condensate. At a rating of 100,000 BTU they will generate about 0.8 to 1.0 gallons of condensate per hour. Over a 24 hour heating period in the middle of winter it will produce 24 gallons of water. The water is acid and corrosive. A good condensate management set-up will be essential to proper function of the furnace.
