Water leaking on floor - WHY IS MY FURNACE LEAKING WHEN THE AC IS ON?Experiencing a furnace leak when your air conditioner is running might cause your heat rate to rise, but don’t worry! Contrary to  what you might think, this issue is often a sign a clogged drain rather than a major malfunction.

Is it an Emergency? 

While not typically a costly repair, addressing this issue sooner than later is a good idea. Persistent moisture and standing water near heating and cooling equipment can cause:

  • Mold and mildew formation
  • Respiratory issues
  • Reduced lifespan of your HVAC system

If you notice this issue, be proactive and contact your local HVAC company!

Understanding Why Furnaces Leak with AC

Central AC systems often lead to furnace leaks due to blocked condensation drainage. This situation is a typical occurrence in HVAC setups, where the evaporator coil’s function creates excess moisture that, if not properly drained, results in leakage around the furnace.

Let’s break it down.

Air Conditioner Units and Condensation: A Common Culprit

Air conditioners naturally produce condensation during operation. In most setups, a drain pipe channels this water to a floor drain. If this drain or pipe becomes blocked, water may unexpectedly appear, often under the furnace.

The Role of the Evaporator Coil

Central to your heating and cooling system is the evaporator coil, positioned above your furnace. Its operation involves:

  • Circulating household air through the coil via the furnace blower motor
  • Cooling and dehumidifying the air, which then returns to your home through ducts
  • Condensing moisture into a pan above the furnace and blower motor, with excess water draining to the floor

A blockage in this drainage system can cause water to overflow onto furnace components.

Steps for Handling Water Leakage

If you detect water leaking from your furnace during air conditioner use, follow these six steps promptly:

  1. System Shutdown: Use the off switch or, if necessary, your fuse box to turn off the system.
  2. Water Cleanup: Quickly remove any standing water to prevent damage.
  3. Filter Check: Ensure your filter is clean.
  4. Vacuum Use: Employ a water-safe vacuum to clear blockages.
  5. Test the AC: After vacuuming, run the AC to check for leaks.
  6. Condensation Pump Test: If no leaks are present, pour water into the pump to verify its function.

Furnace interior system - WHY IS MY FURNACE LEAKING WHEN THE AC IS ON?

No Need to Panic, But It’s Best to Act Fast

In summary, furnace leaks during central AC operation are commonly caused by blocked condensation drainage systems. This issue highlights the interconnectedness of HVAC components, where a malfunction in one part, like the evaporator coil’s drainage, can lead to complications in another, such as the furnace. Regular maintenance and understanding of these systems are crucial to prevent and quickly address such occurrences, ensuring the longevity and efficiency of your home’s heating and cooling systems.

Discover the ClimateCare Difference

Take the worry out of your home’s heating and cooling. Contact Dow’s ClimateCare today to explore our Maintenance Plans, ensuring your HVAC system runs smoothly all year round.

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