Water leaking from an AC outdoor unit can be caused by a few different issues. Identifying the source of the leak is the first step in repairing the problem. Here are some of the most common reasons an AC outdoor unit may leak water and how to fix them.
Condensation Build Up
One of the most common sources of water leaks from an AC outdoor unit is condensation build up. Here’s an overview of this issue:
What Causes Condensate Build Up
- The cooling coils in an AC system remove warmth and moisture from indoor air. This moisture accumulates on the coils and drips into a condensate pan.
- The condensate pan is designed to allow water to drain away from the unit through a drain line.
- If the drain line gets clogged or restricted, the condensate pan can overflow and leak water from the outdoor unit.
Fixing Condensate Build Up Issues
- Clear any debris, algae or mold from the drain line using a stiff wire or drain clearing chemical.
- Flush the drain line with a garden hose to remove any built up gunk or grime.
- Make sure the drain line is sloped properly to promote drainage. Adjust if needed.
- Check that the condensate pan is clean and clear of dirt build up.
- Consider installing a secondary drain line as a backup if clogs are a recurring issue.
Refrigerant Leaks
Refrigerant leaks are another common source of water from an AC outdoor unit:
How Refrigerant Leaks Cause Water
- The refrigerant in an AC system gets very cold as part of the cooling process.
- If there is a leak in the refrigerant lines, the cold refrigerant can condense water from the surrounding air as it escapes.
- This water can drip from fittings, joints or the leak point on the outdoor unit.
Finding and Repairing Refrigerant Leaks
- Have an HVAC technician conduct a thorough leak test on the system. They can pinpoint the exact location of the leak.
- Very small leaks may be repaired by sealing the leak point. Larger leaks will require replacing parts or lines.
- The system will need to be recharged with new refrigerant after repairing leaks. Proper refrigerant charge is critical for an AC system.
Drainage Problems
Issues with the exterior drainage around the outdoor AC unit can also lead to water leaks:
Improper Drainage Causes
- The outdoor AC unit may not be level, preventing water from properly draining away from the base.
- Nearby soil or landscaping may settle over time, blocking drainage around the concrete pad.
- Gutters, downspouts or surrounding landscape grading may route extra water towards the AC unit.
Fixing Drainage Problems
- Re-level the outdoor unit if needed to pitch water away from the base.
- Add an extended drain line to redirect water away from the unit if necessary.
- Use landscaping techniques like French drains or graded swales to route moisture away from the pad.
- Adjust gutters and downspouts to avoid emptying too close to the AC unit.
Rust and Corrosion
Outdoor air conditioning units are exposed to the elements, which can lead to rust and corrosion that causes leaks:
How Rusting Occurs
- Airborne moisture, salt and pollutants slowly break down protective metal surfaces over years of exposure.
- Small amounts of water from condensation can accumulate on metal parts, accelerating corrosion.
- Copper or aluminum coils and lines are especially prone to corrosion leaks.
Handling Rust Problems
- Use sealants or corrosion inhibiting paints to protect vulnerable metal parts.
- Proactively replace older AC system components before leaks develop.
- When replacing parts, look for more corrosion resistant options like coated aluminum or stainless steel.
- Increase drainage around vulnerable components to minimize moisture contact.
Frequently Asked Questions About AC Leaks
What color is the water coming from my AC?
The water from an AC leak is typically clear. Brown, black or colored water indicates additional issues like rust, algae or pipe corrosion.
Where do I check for leaks on an outdoor AC unit?
Focus on the refrigerant lines, coils, fittings and base pan. Leaks typically form at joints and connections first. Rust spots also indicate potential leak points.
Can a small AC leak be temporarily repaired?
Very minor refrigerant leaks may be temporarily sealed using refrigerant leak repair products. However, the permanent solution is to replace leaking parts.
Is it safe to keep using an AC unit with a known leak?
No, operating a leaking AC system can damage the compressor. Refrigerant levels will continue to drop, reducing cooling performance. Repair all leaks promptly.
How often should I check my outdoor AC unit for leaks?
It’s a good practice to visually inspect your outdoor AC unit at least twice per year – in spring and fall. Check for rust, corrosion, pooling water and other signs of leaks.
Conclusion
Identifying and repairing the source of a water leak from an outdoor air conditioning unit is important for proper operation and longevity of the system. Condensation build up, refrigerant leaks, drainage issues, and rusting/corrosion are some of the most prevalent causes. With attention and preventative maintenance, minor leaks can often be corrected before causing major AC system damage. Contacting an HVAC technician at the first signs of an AC leak can help avoid expensive repairs down the road.