Uploaded June 2026 | Updated September 2026, 3 weeks ago
Are your condensate drain calls leaving you stumped? In this video, we break down everything you need to know about HVAC condensate drain troubleshooting — from the field to the fix.
We start with a real-world look at common drain setups and why a quick, temporary solution might seem to work in a pinch but is likely to fail down the road. If you've ever wondered why a unit keeps dripping or why the bottom of an air handler is covered in rust, static pressure is probably the culprit — and we explain exactly why.
A huge part of this video focuses on traps — how we install them, how to spot a bad one, and what changes you can make to do it right. We cover why pre-made traps often fall short in commercial applications with high static pressure, and why trap depth matters far more than width. It all comes down to physics: using the weight of a vertical water column and gravity to keep air from being pulled through the line.
We also get into vents and why their placement is critical depending on the system type. On a split system, your vent needs to be positioned above the drain pan — but on an RTU, the logic flips entirely. Getting this wrong can mean the difference between a safe overflow and water damage inside a building.
Other topics include:
Cutting drain pipe at an angle to prevent suctioning at the bottom
How a loaded filter drives up static and kills your trap's effectiveness
When to loop in a plumber vs. handling it yourself
Red flags to look for during maintenance visits
Whether you're newer to the trade or a seasoned tech, proper drainage is one of the most overlooked — and most expensive — issues in this industry. Get it right the first time.
Read all the tech tips, take the quizzes, and find our handy calculators at hvacrschool.com or the HVAC School Mobile App on the Google Play Store (hvacrschool.com/play-store) or App Store (hvacrschool.com/app-store).
Are your condensate drain calls leaving you stumped? In this video, we break down everything you need to know about HVAC condensate drain troubleshooting — from the field to the fix.
We start with a real-world look at common drain setups and why a quick, temporary solution might seem to work in a pinch but is likely to fail down the road. If you've ever wondered why a unit keeps dripping or why the bottom of an air handler is covered in rust, static pressure is probably the culprit — and we explain exactly why.
A huge part of this video focuses on traps — how we install them, how to spot a bad one, and what changes you can make to do it right. We cover why pre-made traps often fall short in commercial applications with high static pressure, and why trap depth matters far more than width. It all comes down to physics: using the weight of a vertical water column and gravity to keep air from being pulled through the line.
We also get into vents and why their placement is critical depending on the system type. On a split system, your vent needs to be positioned above the drain pan — but on an RTU, the logic flips entirely. Getting this wrong can mean the difference between a safe overflow and water damage inside a building.
Other topics include:
Cutting drain pipe at an angle to prevent suctioning at the bottom
How a loaded filter drives up static and kills your trap's effectiveness
When to loop in a plumber vs. handling it yourself
Red flags to look for during maintenance visits
Whether you're newer to the trade or a seasoned tech, proper drainage is one of the most overlooked — and most expensive — issues in this industry. Get it right the first time.
Read all the tech tips, take the quizzes, and find our handy calculators at hvacrschool.com or the HVAC School Mobile App on the Google Play Store (hvacrschool.com/play-store) or App Store (hvacrschool.com/app-store).
