How to Inspect AC Drain Pan and Condensate Drain Line

May 1, 2018

When warm air passes over extremely cold evaporator coils, condensation forms and drips into a drain pan below. Think of the water droplets that form on a cold drink in summer. Unfortunately, sometimes condensate drain pans and lines can get damaged or clogged and cause quite a mess.

If water is pooling around your indoor air handler, you probably have an AC drainage problem. Left unattended, the water will continue its downward trajectory through ceilings, walls, and floors. Some AC units have an overflow float switch that will turn the air conditioner off if it detects a condensate backup. If your air conditioner won’t turn on, one of the first things you should check is the condensate drainage system.

To prevent the common occurrence of system shutdowns and condensation leaks around your air conditioner, take some time to inspect the drain pan and condensate drain line.

How to Inspect Drain Pan

The overflow drain pan, located underneath your indoor evaporator coils, catches condensate that forms when warm air passes over cold evaporator coils. This condensation then flows into the PVC condensate drain pipe to be directed outdoors.

By using a flashlight and about a gallon of water, you’ll be able to locate and evaluate the condition of the overflow pan and PVC drain pipe. Small holes and even cracks can be patched up with water sealant or epoxy glue. If it is beyond a simple repair, however, it’s best to contact a professional for replacement.

• Turn the central air conditioning on at the thermostat and allow it to run for 20-30 minutes.
• Locate the indoor air handler and look for any evidence of water around the unit.
• It’s possible that your drain line is in perfect working order and it’s a cracked drain pan that’s causing the leak.
• Before removing the access panel and inspecting the overflow pan, turn off power to the air conditioner.
• Use a flashlight to inspect the drain pan, located inside the air handler. Check the opening to the condensate drain line for any obvious backups or debris.
• Clean out the drain pan as best you can. If there is condensate in the overflow pan, you probably have drain line clog.
• Pour a gallon of water slowly into the overflow pan under the air handler and observe the water level in the pan to verify that water drains freely into the secondary drain line.

It’s usually better to replace the entire drain pan rather than trying to fix it. If the crack is small enough, you can use epoxy glue. If there is any significant damage, contact an HVAC technician to replace the entire pan.

It’s important to know that there are typically two different drain pans, one that is permanently affixed to the unit (below the evaporator coil) and other that is further below. While you are able to remove, clean, fix, and replace the auxiliary pan, you will need to contact a professional for any work on the permanent one.

Solution: Check the condition of your drain pan for cracks and leaks. While you may be able to use waterproof sealant to fix the leak, it’s probably better to just replace the drain pan. Homeowners can successfully replace the auxiliary pan themselves, but a professional is required for replacing the permanent drain pan. We recommend cleaning the drain pan regularly to prevent clogged drain lines and curb mold and algae growth.

How to Inspect Condensate Drain Line

• Locate your indoor air handler and look for the white PVC drain pipe coming from the unit and headed outdoors.
• Inspect the condensate drain line (usually 3/4” white PVC pipe) for any cracks or damage. Conduct a visual inspection of the entire drain line (indoors and out) to make sure it is properly draining outdoors.
• Find the PVC cleanout tee (small vertical section of the pipe) and unscrew the cap.
• Insert a funnel and slowly pour a gallon of water down the drain. If the water begins to back up, you have a drain line clog. If water flows smoothly through the drain line, you can eliminate this. Either contact a professional or learn how to clear a drain line yourself.

Regular maintenance for your HVAC unit will keep your condensate line from clogging in the first place. To help keep your condensate line clear, we recommend pouring a cup of vinegar down the drain line every couple of months. This will help kill mold, algae, and fungi before it has a chance of clogging your drain line. Use vinegar for preventative maintenance throughout the year. It won’t damage your drain line.

You can also use bleach to maintain clear drain lines, but only in the summer when your air conditioner is consistently running. Bleach won’t be able to cause any damage or residue if there is a continuous flow of condensation. Another option is using a stiff brush to clean the inside of the drain line as far as you can reach.

However, the best way to prevent clogged condensate drain pipes is by scheduling annual air conditioning maintenance at the very beginning of each cooling season. A trained technician will conduct a thorough cleaning and inspection, including your drain pan and condensate drain line.

Schedule professional AC maintenance this spring before it’s too late! The trained professionals at Service Champions will completely clear your condensate drain line and fix any leaks you may have. Sign up for the MVP Home Maintenance Plan for 2 HVAC precision tune-ups, 20% off repairs, and much more.

• Learn why your air conditioner is leaking and how to prevent it.
• Learn how to clear a condensate drain line.
• Learn what’s included in your professional air conditioning tune-up.

Service Champions is known for trustworthy, on-time home service throughout the East Bay, South Bay, and Sacramento areas.

For more information on taking care of your HVAC system this summer, don’t hesitate to Ask a Champion.