When the air handler (interior unit) of a central air conditioning system or a water heater is located in an attic, both appliances are required to have a catch pan under them so that any water leakage will not cause damage to the ceiling and living area below. The pan under an air handler can have either a safety switch, that will shut off the system when it senses water puddling in the pan, or a drain to the exterior. Most systems have both installed. An attic water heater is simply required to have a drain to the exterior. 

    The drain must terminate at a visible location, so that the leakage can be observed by a homeowner and repaired. The drain piping usually runs across the attic to just past the nearest exterior wall and terminates downward a few inches below the soffit of the roof overhang. If you see water dripping from the small pipe at the soffit, it means that there is leakage from an air handler or water heater in the attic that requires immediate attention.

    Also, see our blog post What is the canister thing about size of a small soda can on a refrigerant line near the heat pump or air conditioner condenser (outdoor unit)?

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  To learn more about heating and air conditioning systems, see these other blog posts:

• How can I find out the SEER of my air conditioner? 

• My air conditioner won't turn on. What's wrong? 

• How can I find out the size of my air conditioner? 

• How can I tell whether the condenser (outdoor unit) is an air conditioner or heat pump? 

• Where is the air filter for my central air conditioner and furnace? I can’t find it? 

• Does an old air conditioner use more electricity as it ages? 

• How did homes stay cool in Florida before air conditioning? 

• What is wrong with an air conditioner when the air flow out of the vents is low?

• Why has the thermostat screen gone blank? 

• Why does it take so long to cool a house when an air conditioner has been off for a while? 

• Why is my air conditioner not cooling enough? 

• What are the most common problems with wall/window air conditioners?  

• Will closing doors reduce my heating and cooling costs? 

   Visit our HEATING AND AIR CONDITIONING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.