A/C drain pan not draining.

IS THE EVAPORATER FAN RUNNING

I am a certified HVAC Technician. I have worked in the field since 1996. I have seen this hundreds of times, if not a thousand times, in the past. Every central air conditioning and heat pump system comes with TWO drain pans, The MAIN drain pan is located within the AIR HANDLER (blower) UNIT, while the EMERGENCY DRAIN PAN is extremely LARGE and sits under the ENTIRE AIR HANDLER (blower) UNIT. The ONLY time water will be INSIDE an EMERGENCY DRAIN PAN is when the MAIN DRAIN PAN condensate drain line is CLOGGED, causing the MAIN DRAIN PAN to overflow. What causes the drains pans OR the drain lines to become clogged is slime and scale from the condensate water as well as debris from within the attic that may have either been blown by the air or may have simply have fallen into the emergency drain pan; or some insects from the out of doors have traveled up into the PVC Drain line and built a nest on the downward side of the P-trap. The P-trap is designed to prevent critters from entering your home through the PVC drain lines. Most CLOGS occur at the P-TRAP location.

The BEST thing to do is:

1. Locate the WHITE PVC drain pipe outside your house and ensure there is NO water draining from it.

2. Locate the same WHITE PVC drain pipe inside your house. You should notice a "TEE" where two WHITE PVC drain pipes merge into ONE WHITE PVC drain pipe.

Follow the below steps, in the order shown:

A. FIRST, find another person to act as your second set of eyes at the end of the WHITE PVC Drain Line that is located outside of your home. That person will be looking for water or debris to EXIT the end of that WHITE PVC DRAIN LINE.

B. SECONDLY, locate the WHITE PVC "P-TRAP" inside your house. It is normally located within a couple to three feet of your indoor air handing (blower) unit.

C. THIRDLY, very gently lift the entire WHITE PVC drain line up in the air as high as you can without breaking it, and slam it down onto the rafters or attic floor or garage floor. You are attempting to dislodge the CLOG within the drain pipe WITHOUT having to actually CUT the PVC and without damaging or breaking the WHITE PVC. Depending on how old the system is, it may or may not be brittle; and it may not take much to damage or break the PVC, which will cause leaks. So, be very careful at this point.

D. Ask the person outside if anything has started to EXIT. You can ALSO usually hear water start to drain if you put your ear up to the drain line. If the person said "NO"and if you don't see the water level getting LOWER in the EMERGENCY drain pan, then REPEAT step "C" above.

E. If the person informs you that there IS water now starting to exit the WHITE PVC DRAIN PIPE, you should then wait until all water has drained from the EMERGENCY DRAIN PAN; and then pour at least 1 quart of BLEACH down that drain, from the EMERGENCY DRAIN PAN exit. The BLEACH will further clear out any SLIME which may be remaining within the "P-TRAP" and will also CLEAN OUT and DISINFECT that drain line.

If the above steps do NOT work for you, then prepare to go into the next LOGICAL phase of your attack. Please NOTE: I am limited to 10,000 characters in my response, so I'll repost additional STEPS in another RESPONSE. Good Luck!!!

The air conditioning coil that cools the car should be in a tray that collects the condensate and drains under the car or perhaps down through the engine compartment. After running the air if you pull into your driveway and stop you should see water dripping. If the drain gets plugged it will overflow the drain pan and drip in the car. This may be what is happening. Look around near the firewall for the drain pipe/hose. Be careful if the engine has just been run.

I assume it is dripping water when the AC is running. If you look at the attic unit, there should be a PVC pipe running from the unit - probably an insulated PVC pipe. This pipe probably goes across the attic to the edge of the house and drains outside. The drain pan may also have a drain pipe, but the one on the AC unit is the issue, and is probably plugged. Go outside and see if you can locate the AC drain pipe. See if the ground is wet below the pipe and if water is steadily dripping from the pipe (with AC running). If the pipe and ground are dry, the pipe is plugged. If you have a wet/dry vac, try connecting it to the drain pipe outside to see if you can **** the pluggage out. If you can get it clear, water should start dripping out of the pipe. This same thing happened at our house. I decided to cut the pipe in the attic, and add in a PVC isolation valve, tee, and water hose connection with plug, so I can valve out the AC unit from the pipe, remove hose connection plug, and hook up a water hose and flush the line to outside. Lowe's sells all of the PVC pipe fittings. The water pressure from the hose will always flush out the algae and crud to the outside of the house. I can also remove the plug and pour a cup of bleach down the drain pipe every couple of months to keep algae growth in check. I also cut out the trap (u-leg) from pipe in the attic and purchased a ready made trap a Lowes (the contractor who built our house had made a lousy homemade trap). I purchased a few PVC elbows and installed the trap on the drain pipe outside. By the way, our AC drain pipe comes out of our wall outside and drains near our outside unit. Our secondary drain pan drain pipe comes out outside from an eave on the side of the house. I don't know what you drain line looks like (it may have a port to add bleach, or some cleanout provisions, maybe not). If you choose to modify/improve it, then make a sketch of it, go to Lowe's and get the PVC parts you need + PVC pipe primer and cement. PVC cement dries fast. Remember, the pipe must flow downhill from you AC attic unit. You can use a regular wood saw to cut the pipe. I hope this helps you. You need to keep the drain line clear as algae will continue to grow in it. Pouring bleach in the line every month or two helps. You also need to check maybe once a month that the line is draining properly (check to see if dripping outside). You can get some serious water damage to your ceilings if the water backs up and overflows. I discovered that our drain line was plugged just in time as our drain pan drain line was also partially plugged and drain pan was about to overflow.

The water is syphoning out the drain hose.
Many times when the stand pipe is backing up someone will seal the washer drain hose to the pipe to avoid overflow of the stand pipe.
This causes the water to syphon from the washer.

Or the opening for the stand pipe is just big enough to put the drain hose in and is to tight causing the syphon.

Putting the drain hose to far down the pipe can cause a syphon also.

I know of two possible causes for water leaking other than the ice maker and water dispenser water supply.
Your evaporator coils frost up in normal use and every eight hours or so the entire unit shuts down and the defrost heater comes on to melt the frost. This cycle last about 20 minutes. The melted frost drips into a drain pan and through a drain tube to the drain tray under the freezer/refrigerator where it's evaporated by the condenser fan.
Your drain tube may be stopped up with ice at the upper end because it drains too slow because it's stopped up at the lower end in the evaporator pan under the unit at the floor. It can get dust and mold in it. Once you get the ice out at the top a little pressure with a turkey baster will usually clear it out. Flushing it out with hot water and clorox may help.
When a water filter gets stopped up, the water can bypass straight to the drain pan underneath and overflow

Make sure that the flexible pipe is securely connected to the drainpan, it can come adrift and cause leaking. The way to check this is to make sure everything is dried out completely. Then open the front grill and carefully pour water so that it goes only into the drip pan. Pour slowly so that you do not overflow the pan. If water is coming out on the outside and you have no leaks on the inside, then you can rule out the perished or disconnected drainpipe theory. In this case your unit may be short of refrigerant causing excessive run time and a freeze up of the evaporator.

The condensate drain line is probably clogged.

Find out where the pipe exits the home, and attatch a wet/dry shop vack to the end of the drain line, close it up around the pipe as much as possible and trun it on.

These typically get clogged with dust, dirt, pet hair, mold etc.
They usually clog at the elbows, P-traps and the inlet coming from the drain pan. There is an internal drain pan in the unit that catches the condensation. When the line clogs the pan overflows and you have water dripping from the unit.

There is also a small chace the pan has a hole in it, but thats fairly rare. There is also a chjance that if the unit is not level the water will overflow the pan before it can drain. (most pans are only 1 to 2 inches deep.) Make sure the unit is level or veryslightly lower toward the drain side.

Refrigerators use different methods to eliminate the water, but they all use evaporation of some sort.This works,as most of the water in the drain pan comes from melted ice on the evaporator coil during the defrost cycle, and this is not very much. It sounds like you have excessive water in the pan. You stated the freezer/fredge is working properly. The condenser fan is running, I assume. Cleaning the dust off the coil will help the air flow. Most residential units do not have heating element in the drain pan. Your problem sounds like you are getting too much water in the pan. Have you noticed excessive ice in the freezer? Are the door gaskets in good shape. Does the unit have water and ice in the door? If so, where does the drain to, and has there been high usage of this?