If you’ve climbed up into your attic and found water sitting in that secondary drain pan under your air handler, don’t ignore it. HVAC Dripping Water from an attic unit is one of those problems that looks minor until it absolutely isn’t — and in Drexel Hill, where a lot of homes were built with the air handler tucked into a finished attic space, a slow leak can quietly damage drywall, insulation, and even structural framing before you ever notice a stain on the ceiling below. I’m Yan, and after 20-plus years doing residential ac repair across Delaware and Chester County, I can tell you: the secondary pan filling up is never the actual problem — it’s the warning sign that something else has already gone wrong.
Why the Secondary Pan Exists (and Why It Filling Up Is Bad)
Every attic air handler installation is supposed to have two drain pans. The primary pan sits directly under the evaporator coil and drains through a condensate line — usually to the outside or into a utility drain. The secondary pan sits beneath the entire unit and is only supposed to catch water if the primary system fails. Think of it as the last line of defense.
So if your secondary pan has water in it, that means your primary drain has already failed. The question is why.
The Most Common Causes of HVAC Dripping Water from an Attic Air Handler
- Clogged primary condensate line. Algae, mold, and debris build up inside the drain line over time — especially in humid southeastern Pennsylvania summers. This is the number-one cause we see across Drexel Hill and the surrounding Main Line communities.
- Frozen evaporator coil. A dirty air filter, low refrigerant, or restricted airflow causes the coil to ice over. When it thaws, it dumps far more water than the primary drain can handle. If you’re also noticing your house not cooling below 78 on hot days, a frozen coil is a strong possibility.
- Cracked or corroded primary pan. In older homes with systems that haven’t been serviced in years, the primary pan itself can rust through — especially in the humid conditions common to older Delaware County housing stock.
- Improper pitch on the drain line. If the line doesn’t have the right slope, condensate pools instead of draining. We see this a lot after DIY repairs or rushed installations.
The secondary pan is doing its job — but its job is to buy you hours, not weeks. Once it’s full, the next stop is your ceiling.
What You Should (and Shouldn’t) Do Right Now
First, turn the system off. Running an AC with a compromised drain situation can cause the secondary pan to overflow and make the water damage significantly worse. Check your air filter — if it’s packed solid, that alone could be causing a coil freeze-thaw cycle. Replace it immediately.
Do not try to shop-vac the secondary pan and call it fixed. That water is a symptom. The blockage, cracked pan, or refrigerant issue causing it is still there. Humidity issues in southeastern Pennsylvania homes are serious — mold can establish itself in attic insulation within 48 to 72 hours of a water intrusion. If you’re already concerned about moisture in your home, our post on ideal indoor humidity levels in summer is worth a read.
If you’re finishing or planning to use your attic space, a leaking air handler is exactly the kind of issue to resolve before you invest in the buildout — we cover the HVAC considerations for attic spaces in detail here.
What a Proper Repair Actually Looks Like
A thorough diagnosis covers the full condensate system: flushing the drain line, inspecting both pans for cracks or rust, checking refrigerant charge, and verifying airflow through the coil. According to the U.S. Department of Energy, routine maintenance — including keeping condensate drains clear — is one of the highest-impact things you can do to protect your system’s efficiency and lifespan. Expect a service call for a clogged drain and flush to run in the $100–$250 range; if there’s a cracked pan or refrigerant issue involved, costs go higher depending on the scope.
The homeowners we hear from most often — landlords in Drexel Hill managing older properties near Burmont Road, or families in the Drexel Hill neighborhoods off Township Line — usually waited longer than they should have because the first company they called either missed the root cause or didn’t explain it clearly. If that sounds familiar, we get it.
We serve Drexel Hill and the surrounding Drexel Hill area, and our technicians know these houses. If your attic drain pan has water in it, call Air Pro HVAC at (215) 240-8466 before that secondary pan becomes a ceiling replacement.
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