It’s not uncommon to find a puddle of water around your furnace, but this is a problem that should not be ignored.
The very thought of a leaking furnace while the AC runs is worrisome and may be an indication of a clogged drain or a malfunctioning evaporator coil.
Though these issues aren’t too costly to repair, they need your urgent attention and inspection from a licensed professional. That’s because standing water and constant moisture around the HVAC equipment can result in mold, mildew, breathing issues, and irreparable damages to the system.
First Things First
If you notice that your furnace is leaking with the AC on, turn the HVAC off stat. If the off switch is too far out of your reach or you simply don’t remember where it is, go to the fuse box to turn it off.
Next, please clean up the standing water to keep it from damaging the floor or carpets. It also poses fire and electrical hazards if it gets near an outlet, so better to be safe than sorry.
Now, let’s figure out what caused the leak in the first place and how you can deal with it in the best way possible.
Possible Causes Of Water Leakage From The Furnace
Under normal working conditions, air conditioners produce water that is expelled as condensation through the evaporator coil. The water is channeled through a small PVC drain pipe, usually not more than ¾ inch, and discharged through a sump pump or any other kind of drain, such as a floor drain.
When everything is working fine, the only detectable sign of water flow would be a dripping sound. So you should only expect to hear the water flow and not find any visible evidence of it around your indoor system. If you notice any water puddles, it’s a sign that the furnace is leaking water when AC is on due to some malfunction within the system.
Most water leakage risks can be avoided in time if you conduct regular maintenance on your air conditioner from time to time. However, if you start noticing water around the furnace, it’s a sign that the leakage has persisted for some time and needs to be addressed immediately.
It might have happened because of the:
Faulty HVAC Evaporator Coil
Your furnace leaking water when AC is on could indicate issues with your evaporator coil. This coil sits as a series of piping on your system, and it is essential for the proper functioning of your heating and cooling system.
As systems age, dust and dirt can collect on the evaporator coil, eventually plugging up the drain line. With this restriction, the water pushes back into the coil and eventually spills onto the floor.
Then, the furnace motor blows air through the evaporator coil, absorbs the heat, cools it down, and recirculates it through your house as chilled air. It is also responsible for dehumidifying your home by condensing it into water.
If the drain is clogged, the water ends up overflowing back to the motors, burners, and evaporator coil.
Plugged Filter And Drain
A plugged filter can restrict the amount of air flowing through your coil. Unfortunately, this usually results in a frozen coil and a leaky furnace when AC is on.
The furnace and the air conditioner generally share the draining outlet. If the drain happens to be clogged, it can result in the furnace leaking water when AC is on since the water has nowhere to go. All you need to do is unclog the draining outlet in that case.
Leakage In The Drain Pan And Plumbing
If water is left to sit on the pan under the coil for too long, it can cause holes to develop due to rusting, eventually allowing water to drain through it and leading to leakage.
Many times, it might not be the furnace that is causing the leakage. Instead, your plumbing could have issues, such as clogged and broken pipes, which can present the same leakage symptoms as a broken furnace. Repair or replace these pipes at the earliest, as the clogged water can damage the furnace.
Condensate Pump Problems
Suppose your air conditioning system has a condensate pump. In that case, it can be another cause for water draining and leakage, as it is another electrical component that poses a risk of breaking down.
Most often, a leaky furnace comes from a condensation leak. Many furnaces run at an AFUE rating of 90 or above. AFUE stands for Annual Fuel Utilization Efficiency and thus refers to how efficient your furnace is.
This leads to heavy condensation, which is transported out through the furnace pipes into the drain. If there is breakage or clogging within these pipes, the condensation can accumulate at the bottom of the furnace.
How To Stop Water Leakage From Your Furnace
Check your filter to make sure that air flows through it without any obstruction. Then use a water-safe vacuum to remove any debris, dust, and sources of potential clogs from the PVC drain line. Finally, turn on your air conditioning system to check if this has fixed the leak.
Once you are confident that there are no leaks anymore, pour some water into the condensation pump to see if it’s working fine. In case the pump doesn’t react, you have a mechanical failure at your hands. But if it starts to pump water, it indicates that the line from the pump to the drain is absolutely fine.
Also Read: Ac Fan Won’t Turn Off (We have Fix!)
In Conclusion
It’s crucial to catch these HVAC problems before they become a significant problem. And that starts with regular HVAC maintenance.
Make sure you schedule visits with your local HVAC technicians at least twice a year to keep your system in optimum working condition. They clean the drain, replace filters, and do system-wide checks to ensure that all components are the way they should be.
But more importantly, call them up to deal with problems like leaky furnaces and ensure your complete peace of mind.
