Why Is My Furnace Leaking Water When The AC Is On? (Fix It Now!)


Why Is My Furnace Leaking Water When the AC Is On

There comes a time when problems arise with the furnace or the AC unit. One of the most common issues is finding water around the furnace when the AC is running. The first question we ask is what is causing this problem.

When water is around the furnace while the AC is running usually means frozen coils, condensation, or overflowed drain pan. It can also mean clogged or leaking drain lines. A chain of events can cause any of these situations, and you can follow a checklist to find the source.

You can find the source of the problem before calling the professionals. If it deals with something mechanical or electrical, it is best not to fix it yourself. However, there are a few things you may find that may solve the problem.

Frozen Coils and The Weather Can Cause Water Leakage

In climates where the AC is running one day and the heater the next, you may find water leaking. Sometimes the coils freeze up when the weather is unpredictable in temperatures. When they thaw out, the water goes into the drain pan and may overflow onto the floor.

It is a combination of the weather and one of these three things that cause the evaporator coils to freeze.

  1. An air filter in need of changing will block the warm air from going into the AC system. If there is no warm air getting to the evaporator coils, they will freeze up. The air filter is something you can change yourself and may solve the problem immediately.
  2. A restricted airflow from blocked or closed vents affects the evaporator coil the same as a dirty filter. The air needs to circulate throughout the home. If you close the vents to a room, open them and see if it stops the coils from freezing.
  3. A unit low on refrigerant caused by a leak will not remove the warm air from the evaporator coil. The unit should never lose refrigerant, but if it does, the evaporator coils will ice up. Please note that refrigerant is a hazardous substance and should only be handled by a licensed professional.

Please keep in mind; the weather is a small factor. When it is cooler outside, and the AC is running, the factors listed above will make the situation worse. The evaporator coils freezing up is a sign something is wrong.

Condensation and Plumbing Issues Causing the Leaks

Hot air and cold air mixing will always cause condensation. The way the heating and air conditioning system operates is through both exchanges of hot and cold air. Hot air needs to be carried out of the home through the pipes.

Plumbing issues will cause condensation to build up and overflow in the pipes if they are clogged or broken. It is a drain pipe that goes through the floor. Water will back up through the lines onto the floor, causing damage to the floors if the problem goes unrepaired.

Many people are good with plumbing. If you are one of those people, you can fix it yourself by replacing the pipe if it is broken. For a clogged line, all you have to do is flush it out.

The air condition will always leak and fill the condensation pan in cooler temperatures. It will drip down to the heating system when it overfills, making it look like the furnace is the problem. Keeping up with the plumbing will keep the issue at a minimum, but constant leaking calls for a professional.

Doing it Yourself or Calling a Professional

There are times when we seize the opportunity to handle the repairs ourselves. The knowledge or experience allows us to work with our hands and save money. When it comes to AC and heating units, it can be dangerous if we are not HVAC Certified.

Easy fixes like the plumbing, changing a filter, opening the vents are significant when solving the troubleshooting issues. Repairing the technical or electrical problems yourself can cause fires, more water damage, or damaging the unit. It also takes a license to purchase the refrigerant if low, and you cannot buy specific parts without certifications.

Those are the times a person has no choice but to call in the professionals. If you follow all the troubleshooting from the owner’s manual, there is nothing more you can do. Some of the component issues may be the following:

  1. The heat exchanger.
  2. Something in the vent system is blocking the airflow.
  3. Broken or clogged humidifier.
  4. The evaporator coils may need to be replaced.
  5. Broken Condensate Pump.
  6. The return airflow unit

The Steps to Diagnosing the Problem

When noticing the leak, action needs to be taken right away. There are steps you can take to find the problem to help save time and money. A few companies offer free estimates, but others will charge as much as $100 for diagnosing the issues.

Sometimes you may not find the source, but you may save money if you follow these steps.

Step 1: Shut the Power Off to the Unit

Turn the power off at the AC unit or the heating unit. Go to the breakers, look for the AC unit and the furnace breakers, and flip them to the off position. Safety first because we all know water and electricity do not mix.

Step 2: Dry Up All of the Standing Water

Use towels or a mop to clean up the spillage all around the base of the furnace. You may need to rent a wet/dry cleaner if the water is overwhelming. Everything must be dry before moving on to the next steps.

Step 3: Change the Air Filter

Believe it or not, this step may end all of your problems with leakage. About 60 percent time, the water you will see on the floor is due to a dirty filter. Run the unit for up to 24 hours, continually checking for more leaking.

If the leaking stops, then the filter is what was causing the leaks. Continue to the next step if there is still water on the floor.

Step 4: Check for Condensation and Drainage

Try to locate where the water is leaking. It could be from condensation, frozen coils thawing out, or clogged drains. If it deals with the plumbing and you are 100 percent confident, go ahead and fix it.

Step 5: Call a Professional If Nothing Is Found

If you are not 100 percent sure about repairing the plumbing or drainage, contact an HVAC Certified Technician. The steps for the DIY end here if the problem is not located. Unfortunately, it could be with the components themselves.

Approximate Costs To Repair a Leaking Unit

There could be different things wrong that will affect the costs of repairing the leakage. The average labor cost from a professional runs between $100 to $450. If the furnace went bad, it could run from $700 to over $3000 in parts or replacing the unit.

Solar units can go as high as $6,000 if a replacement is needed. The prices also depend on what type of units you are purchasing. The most expensive of the group is the solar-powered units.

The same could be said for the AC unit between $700 and $3000. Most of the time, the return air is the most expensive part to replace if it goes that far. It depends on how old the unit is and if the homeowners kept up with the maintenance.

If you find the filter or the pipes were the culprits, small repairs are not that expensive. If you have to replace the drainage pipes, it may run about $50 to $75, depending on the pipe’s material. The air filters cost between $50 to $85.

Related Questions

Does Home Owner’s Insurance cover the parts and labor for repairs on my AC or heating unit?

Every insurance and state is different, but the wear and tear answer is no. Home Owner’s Insurance will not cover the repairs or replacement unless damaged by fire, flood, or other natural disasters.

There are, however, insurances you can purchase for added warranties from the manufacturer. Also, some insurances cover repairs for home appliances. Those must be dealt with caution and read the fine print.

What will happen if I cannot repair the leaking water quickly enough?

Several things can happen if water sets too long on the floor. The floor will rot, mold and mildew will become a problem, and the water can further damage the floor. Also, the unit could face further damage if the problem is not fixed.

On average, the longest you can leave the leak is a week at best if you continue to soak up the water. If money is the issue or professional help cannot arrive in amp time, turn the unit off at the breaker.

How long does a furnace last?

On average most can last problem-free for up to 15 years, depending on the maintenance and upkeep.

Upgraded Home Team

We are a team of homeowners and home improvement enthusiasts who enjoy sharing decorating, gardening, home improvement, and housekeeping tips with other homeowners! Whether you're looking for advice on furnishing your living room or the next outdoor DIY project, we've got you covered.

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