Water leaks at my indoor unit

(Today's mechanical code requires an auto safety switch to be installed on all new equipment to protect against water damage)

Under no circumstances should you ever see water around the indoor unit. This is a sign that something is either leaking or dripping not draining. Although it needs prompt attention, sometimes it is only a very minor problem.


In the cooling mode, the indoor evaporator coil and the suction line sweats. That's why it is wrapped in black insulation. If the insulation is missing or has been torn or split, it can cause dripping. Obviously this is easy to repair.


The evaporator produces a lot of water during the summer as it removes excess humidity from the air. The water runs down the outside of the coil into a pan that has a drain. The drain goes outside the house into a gutter or directly to the ground.


If the coil is dirty, the water mixes with the dirt; the dirty water ends up in the pan, the drain trap or anywhere else it can cause a problem. As the water flows by gravity, it doesn't take much dirt to clog a drain and if your coil is located in the attic or finished room, serious damage can result. This is a very important reason for having clean filters and an annual inspection that includes coil cleaning.


Sometimes the indoor coil actual ices up. When the ice melts, excessive water all over the floor or ceiling is the result.


Indoor water problems are not just limited to summer. Some of today's high efficiency furnaces also produce condensation, which must be drained. A central humidifier also can cause leaks. All of these things emphasize the necessity for annual inspections plus you should always keep your eyes open for water, as it is a sure sign that something is amiss. Sometimes it is a simple fix; sometimes not.


Below is a list of possible causes and things to check. Items in blue can be addressed or fixed by the homeowner. Those in red usually require a service call.


  • Suction line missing insulation

  • Drain line moved or not pitched downward

  • Floor drain clogged with dirt

  • Leaking humidifier


  • Blocked pan, trap or drain

  • Indoor coil frozen due to malfunction

  • Dirty or defective evaporative coil

  • Cracked condensate pan

  • Broken fittings or pipe; unglued joints

  • Kinked tubing Humidifier over filling or leaking


Hope this has been of some assistance, however they are just rough guidelines and not all possible conditions are covered.




The company You Choose To Install and Service Your System Will Determine The Degree of Comfort and Satisfaction You Enjoy.

Excerpts of the preceding information have been compiled by Hannabery HVAC, which has graciously permitted us to include them on this web site as a service for all homeowners.


These " Common HVAC Problems " are provided FREE and as a consequence Climatemakers does not assume any liability resulting from any information we provide. In all cases where there is any possibility of injury, consequential damage, direct damage to your equipment or when recommended by the equipment manufacturer, your system should be repaired, inspected or maintained by a qualified technician.


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