1 Answer

Top 6 reasons

An air conditioners primary job is to remove moisture from the room to give you a feeling of comfort. During this process they capture a lot of water. How much, is dependent upon humidity content of the air, size of the air conditioner, its operating efficiency, and whether it was properly installed. The water captured during normal operation flows down the cooling coil and drops into the base, following channels or passages to the rear. Some of the water is lifted up by the fan blade and used to cool the heating coil, while most of it proceeds to the rear where it drops out of the base and onto the ground. That is, if everything is working perfectly. The reality of window air conditioners is that they can leak water.

The source of the leak can be allusive,  appearing to come from multiple places, or only happen sporadically. Whichever the case, an air conditioner that leaks can drive you crazy trying to find the cause of the problem. The following are a few suggestions of the most common reasons why water leakage occurs. 

1... Improperly installed 
A window air conditioner must be installed so that it's slightly lower at the rear than the front. This allows the water being removed from the room to drain to the back of the machine. A difference of one inch is sufficient. This is always the first thing to check. Many are improperly installed in the haste to get relief from the heat. If installed too low at front the water will flow into the room rather than outside. If installed too low at rear, water can roll out the front edges before it has a chance to exit towards the rear drain. 

2... Icing up 
Water being de-humidified from the room air can turn to ice if there are problems with the cooling system. There are many reasons for an air conditioner to produce ice. Remove front grille while machine is operating. If ice is present on the cooling coil you will probably need service. For more information about icing up see our article, ' Why window Air Conditioners Ice up'.  

3... Air leakage around air conditioner 
If warm air from outdoors is able to enter around the air conditioner it will encounter cooler, dryer air. When they meet condensation will occur. If water is leaking from front of air conditioner inspect area to see if dripping from body of machine, or water droplets clinging to front area. To test, operate machine for 30 minutes and then use flashlight to check under front edge of base. Small water droplets here indicate an air leakage problem. Add foam insulation to stop warm air from infiltrating. 

4... Drain hole blocked 
The rear of air conditioner base has a drain hole or notch to allow water to escape. If it becomes blocked water can back up. To test, operate machine for 30 minutes and then inspect if draining properly at rear. The base should contain a substantial amount of water, but not to the point where the whole base is completely full of water. If appears blocked use a small piece of wood (a popsicle stick or wooden skewer works well) to open drain hole at rear of metal base. CAUTION: Never be tempted to drill holes into the air conditioner body to relieve water pooling. Severe damage can result. 

5... Internal drains blocked 
There are small passageways that allow water to drain from front of air conditioner to the rear. If they become blocked water will pool at front of machine and overflow onto floor. If this happens the air conditioner will require removal from window and servicing. To test, operate machine for 30 minutes and then remove front filter and plastic cowling. If front of base completely full of water, but little dropping from rear of machine onto ground, suspect blocked passageways.

6... Outside temperature too cold 
This problem is more common near the end of cooling season. If outside temperatures drops below 60 degrees Fahrenheit at night the cooling coil may ice up. If no leakage at bedtime but water in front of machine in morning, suspect this problem. If this problem suspected turn off machine before bedtime and restart as day warms. Alternately, operate machine at night with selector switch in ‘fan only’ position. This will circulate room air during night, but not allow cooling and the subsequent water leakage.

  By Donald Grummett 

Copyright © 2006 Donald Grummett. All rights reserved

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