Furnaces
Frozen condensate drain: how to fix it yourself
By Tom Moor•December 17, 2024
If your furnace abruptly stops working when it’s below freezing outside, you may have a frozen condensate drain. In most cases, you can fix this yourself.
Keep reading for directions on how to repair a frozen condensate drain. If you’re not up for DIY, no worries! Click the box below, and we’ll connect you with a vetted local dealer who can help you.
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Locating your HVAC condensate drain
Your condensate line drains condensation created by your HVAC system out of your home. It is usually a white PVC pipe on an exterior wall from inside to outside your house. Sometimes, it’s near your condenser.
If the water inside the pipe freezes, your furnace can no longer properly drain condensation. As a safety measure, it will shut itself off until you clear the drain.
Fixing your frozen condensate drain
Once you’ve located your frozen condensate drain, there are a few ways to defrost it. Make sure to turn your furnace off at the fuse box first.
| 💧 Use a hot water bottle | Heat water on your stove or run hot water from your tap. Fill a stainless steel water bottle or thermos with the water. Affix it to your condensate drain line with a bungee cord or other fastener. Keep it there until the water inside the drain melts and your furnace works again. |
| 🫖 Pour hot water | Fill a vessel like a kettle with hot water. Take the vessel outside and slowly pour the hot water over the condensate drain until the ice melts. You might need to do this several times before the line defrosts completely. |
| 💨 Heat with a hair dryer | Connect your hair dryer to an extension cord. Choose its highest heat setting and point it at the drain, warming it until the ice melts. This may take 20+ minutes. Make sure it’s not raining, snowing, or otherwise wet outside if you choose this method. |
| 🔥 Bring your space heater outside | Connect your space heater to an extension cord or use a battery-powered heater. Place it near the condensate drain to warm it and melt the ice inside. Do not leave the heater unattended. Do not choose this method if it is unsafe to use electrical appliances outdoors. |
Be careful not to burn yourself or damage your HVAC equipment. Never use electrical appliances in rainy or snowy conditions.
Do not use boiling water on your frozen condensate drain. It may crack your pipe.
Once your drain line is ice-free, turn the furnace back on at the fuse box. It should work as expected.
If the weather remains cold, your condensate drain may freeze again. Simply repeat the process and consider hiring an HVAC technician who can take measures to prevent the condensate line from freezing in the future.
How to prevent condensate line from freezing
The most straightforward way to keep your condensate line from freezing repeatedly is to insulate the pipe. You can try to do this yourself with an insulated wrap.
If that doesn’t solve the problem, call an HVAC contractor. There may be more factors at play, such as the slope of the pipe or a clog unrelated to the cold weather.
If your condensate drain line is especially long, it might help to shorten the pipe, leaving less opportunity for freezing. For example, if your drain pipe leads under the house, through your crawl space, and out to the yard, you may benefit from shortening it.
A licensed furnace contractor can conduct this repair for you, cutting the condensate line and redirecting it to drain elsewhere.
Click below to connect with an HVAC technician who can examine your condensate drain line and recommend a course of action to prevent freezing.
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Furnace troubleshooting
If your furnace isn’t working and defrosting your condensate drain line doesn’t help, check out our furnace troubleshooting tips. Performing these simple tasks may fix your issue and save you the expense of a professional repair.
If troubleshooting doesn’t solve your problem, it may be time to call in an expert. HVAC.com can connect you with a top-rated local furnace contractor to diagnose and perform a repair. Click below to schedule an appointment.
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