One of the most obvious signs is a puddle of water in your AC's drain pan, which proves the water isn't draining as it should. Other signs include: Standing water near your air conditioner's condenser unit. A moldy smell around the drain or from your system's vents and registers.
Common condensate issues
Common ways to identify if your condensate pipe is blocked are listening for an unusual gurgling sound when the boiler attempts to start, or the boiler may repeatedly 'lock out' or stop working and display an EA code.
Removing clogs
Vacuum the standing water from the condensate pan with a wet/dry vacuum. Insert a plumber's snake or plastic tubing into the PVC drain attached to the pan to remove obstructions, then do the same on the terminal end of the drain.
Attach a wet-dry vacuum or shop vac hose to the end of the AC drain line, using tape to make a seal. Run the vacuum for a few minutes to suction clogs out of the line.
Locate the white plastic pipe that leads outside, then check for any blockages like debris or ice. Defrost ice with warm water, not boiling, and use a rod or wire to push through the obstruction. If that doesn't work, call a pro with specialist equipment.
Your AC has a condensate drain line running from the indoor to the outdoor unit. You'll find the end of the drain line somewhere near the outdoor unit (usually a copper or white PVC pipe). As for the access point, look for a vertical pipe with a cap near the indoor unit.
Check for clogs
Make sure you don't run the condensate pump without any water in the reservoir since this can damage the device. If water comes out of the drain hose then you know that the hose is not clogged. If the water doesn't come out of the drain hose then it's possible that there is a clog.
A very useful diagnostic aid is the “Feel Test”. As the test implies it is a matter of quite simply feeling tubes and components for temperature drops, indicating possible blockage location. By this stage you would be aware of what side of the A/C system should be hot and what side should be cold.
The AC coil cleaning cost is around $100 to $400 as of 2024, according to Homeguide (for an evaporator coil), and up to $700 to remove and clean the coil. Cleaning the condenser coil costs $75 to $230.
A clogged condensate drain line will trap water in your air conditioner. As a result, the evaporator coil will eventually turn to ice. The moisture in the drain line can also freeze, which will cause your air conditioner to turn off. But before it does, it'll likely suffer some damage.
Flush Condensate Drain Line
The repair cost to have the drain line flushed runs between $75 to $250.
Flush With Vinegar
Pour ¼ cup of distilled vinegar into the opening of the drain line. Distilled white vinegar is preferable for this job as its high acidity levels work hard to remove the buildup lodged in your drain. If you don't have any vinegar in the house, you can use peroxide as a substitute.
It's completely normal for your AC to drain 5-20 gallons of water outside of your home (via the condensate drain).
Over time, this line can become clogged with algae, dirt, dust, and debris. When this happens, the line backs up and overflows from the drain pan, causing the water to leak into your home. You can unclog the drain line by removing the debris with a wet/dry vac.
Look for the presence of water around the boiler or an overflowing condensate tray, both signalling a potential blockage in the pipe. Listen for gurgling or dripping noises coming out of your boiler. This suggests the water is not draining and is causing a blockage.
Leaks with a constant flow rather than slow drip can mean a condensate pipe has become disconnected or punctured. If that's the case, it's important to get your HVAC system serviced as soon as possible to avoid additional problems including further damage to your house.
You'll find a white PVC or copper pipe located near your outdoor unit—this is where the drain line ends. Near your indoor unit, you'll find a vertical PVC pipe with a cap on it, which acts as the access point for the condensate drain.
Simply pull the plug out or flip the switch to the “off” position. Step 3: Use gloved hands to remove any large pieces of debris on or around the outdoor unit. Step 4: Carefully vacuum the condenser fins with a soft-brush attachment.