Furnaces keep millions of Americans warm each winter, and while they are a necessity in some regions, they aren’t without their issues. Even the best furnace can have problems with a condensate pump, which can lead to a variety of issues sooner than later. While it’s easy to tell if a condensate pump is working, diagnosing other problems can be more challenging
Furnace Condensate Pump Doesn’t Work

One of the most straightforward issues with a furnace condensate pump is when it fails to work altogether. Fortunately, this is often easy to diagnose. The problem typically lies with power supply or parts failure.
1.Power Issues: If the pump is plugged into an outlet, ensure that it’s properly plugged in. For hardwired systems, check the switch for the pump to ensure it’s in the “On” position and verify that no breakers have been tripped. Power issues can often be the culprit, and this simple check can save you a potentially costly technician visit.
2. Pump Failure: If the system has power and no breakers have tripped, the pump itself may be malfunctioning. Condensate pumps are responsible for removing moisture from the furnace. If they fail, excess moisture may accumulate, leading to water damage or even mold growth, so it’s important to address this issue quickly.
Furnace Condensate Pump Keeps Running
A furnace condensate pump that keeps running and won’t shut off is a common problem, but it’s often caused by several potential issues. The most likely culprits include:
- Stuck Float: The float inside the pump triggers a switch when the water level reaches a certain point. However, the float can get stuck due to dirt or poor line placement, which causes the pump to run continuously.
- Clogged Check Valve: The check valve prevents water from flowing back into the pump. If it becomes clogged with debris, the pump can run non-stop. Luckily, check valves are usually easy to clean or replace, although some older models might be harder to find replacement parts for.
- Poor Line Placement: Sometimes, the lines inside the pump may be poorly positioned, causing the float to malfunction. Regular inspection and cleaning can help avoid these issues.
Furnace Condensate Pump is Leaking
If you notice water pooling around the condensate pump, it could be leaking. Identifying the source of the leak can sometimes be challenging, but there are several things to check:
- Reservoir: First, check the reservoir. Remove it, fill it with water, and check for any leaks. If the reservoir is in good shape, the issue might be with the discharge line.
- Condensate Line Blockages: PVC drain lines are especially vulnerable to blockages caused by dirt, debris, or even pests. Regularly inspect the drain line, especially if it leads outdoors, as leaves and debris can accumulate and clog the system.
- Improper Slope: Ensure that the drain line is properly sloped. If it’s not, water may back up, leading to potential overflow and leakage.
Furnace Condensate Pump Making Noise
Unusual noises from a condensate pump are often an indication of an underlying issue. Some common noises include:
Whistling: This could indicate an air leak within the pump, which is preventing the system from operating efficiently.
Gurgling: This may be a sign of a clogged line or a pump that’s starting to fail. Gurgling noises can also indicate that the pump is struggling to remove the moisture effectively.
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Loose Parts: Noise can also come from loose discharge fittings or other parts of the pump. It’s important to check that all connections are tight to prevent vibration and unnecessary sound.
Quality Issues: In some cases, the noise may simply be due to poor-quality pumps or issues that weren’t addressed during quality control. This is more common with budget models, although it’s rare with reputable brands like Little Giant.
Furnace Condensate Pump Maintenance
Condensate pumps are designed to be reliable, but problems can occur regardless of how well-built the unit is. That’s where maintenance comes into play as stuck floats and blockages burn out plenty of condensate pumps every year or cause water damage.
We recommend inspecting the condensate pump on your furnace at least once a month so you can stop problems before they start. If you notice build-up in your lines or want to clean the pump every few months, nothing could be easier. You’ll only need a thin bottle brush that can fit into any lines on the system and some canned air to clear any blockages hidden to the naked eye.
- The first thing you need to do is shut off the power to the condensate pump. If it’s hardwired, you’ll need to cut power to the unit itself at the breaker box before attempting to clean the unit. Otherwise, simply unplug it from the power outlet.
- Disconnect the PVC tubing running to the pump. There will be a line that runs directly to the furnace and another that’s tied to the drain line. When the lines are removed, the pump will be free to clean as needed.
- Use canned air to blow through the PVC lines and clear any blockages. If the brush is small enough, you can run it through the lines as well to loosen any debris beforehand. If the PVC tubing looks damaged or worn, now is the time to replace it.
- Make sure the bottle brush is clean, and then use it on the openings where the tubing is inserted into the machine. This will clear any debris that has accumulated inside the openings for the discharge and intake lines.
- Take the reservoir and look it over for any damage or serious signs of wear. You can wipe any gunk out with a paper towel before rinsing it in a sink if you don’t have an outdoor hose with pressure.
- Take the pump itself and use canned air to remove anything that may be lodged near the switch assembly or in other nooks and crannies. You can then “rinse” the pump itself to remove any access debris, but don’t soak the motor. It only needs a light rinsing, not a complete bath.
- Reattach the water reservoir and replace the tubing on the condensate pump. Be careful how far the tubing is inserted so that it does not interfere with the float inside the condensate pump.
- Connect the condensate pump back to the furnace making sure everything is tight and properly connected, and then restore power to the unit. If you want to test the pump to make sure it’s working for additional peace of mind, just follow these steps.
How to Prevent Furnace Condensate Pump Problems
Preventing problems before they start can save you time, money, and the hassle of dealing with water damage or costly repairs. Here are a few tips to keep your furnace condensate pump working efficiently:
- Regular Inspection: Make it a habit to inspect your condensate pump regularly, ideally once every few months. Check the condensate line for any potential blockages, and look for visible signs of wear and tear on the pump, reservoir, and lines.
- Install a Backup Pump: If you live in an area with high humidity or your furnace is prone to condensate issues, consider installing a backup condensate pump. This can help prevent system failure during heavy use or in the event of an issue with your primary pump.
- Maintain Proper Drainage: Ensure the drain line is clear of debris and properly sloped. A blocked or improperly installed drain line can quickly lead to overflow and moisture buildup in the system, leading to expensive repairs.
- Use a Drain Pan: Installing a drain pan under the pump can help catch excess water if there’s a leak or overflow. This can prevent water from damaging surrounding areas and give you a visual cue if something goes wrong.
Signs It’s Time to Replace Your Furnace Condensate Pump
While regular maintenance can extend the life of your condensate pump, there comes a point when repairs may no longer be effective, and replacement is necessary. Here are some signs that your furnace condensate pump may need replacing:
- Constant Leaks: If your condensate pump is leaking even after you’ve replaced seals and checked for clogs, it may be time to replace it. Prolonged leakage can damage the furnace and other areas of your home.
- Persistent Clogs: Despite regular cleaning, if your pump continues to become clogged and doesn’t perform as expected, it may indicate that the pump is starting to fail.
- Unusual Noises: Persistent unusual noises, such as grinding or loud gurgling, can be a sign that the pump’s internal components have worn out. If these noises are present despite your maintenance efforts, it could mean it’s time to invest in a new pump.
- Age of the Unit: If your condensate pump is over 10-15 years old, it might be less efficient or near the end of its life cycle. Newer models are more energy-efficient and can save you money in the long run.
Conclusion
Now that you understand some of the common problems with a furnace water pump, you can set a course of action to prevent issues with the pump before they occur. Maintenance is key, although it’s important to keep the cost of repairs in mind as well with older models compared to the price of a replacement.
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