Common Causes of HVAC Leaks
HVAC Condensation Pan Leaks:
When air conditioning units operate, they collect condensation. HVAC units typically have internal sheet metal pans that collect and drain off the condensation water. Because this is a continuing process, the sheet metal pans have a tendency to rust out. When this happens, the water inside the HVAC unit can leak into the building. This is a common source of leakage, particularly in older units. It represents a significant percentage of the reported leak calls that we receive. If you experience “roof leaks” when it’s not raining, the chances are that it’s an air conditioning problem.
HVAC Air Duct Leaks:
Sometimes HVAC units have sheet metal air ducts that run across the roof. These ducts have overlapping seams, where they are connected together. These seams are sealed to prevent air from leaking in and out. But, they are also sealed to prevent water from getting inside. Unfortunately, these seals can crack and wear out. When the HVAC units operate, a high vacuum occurs in some of the ducts. If the duct seals are cracked or broken, the vacuum can pull rainwater inside. Once inside the ducts, the water can be blown through the system. If you experience leakage that is seen directly below air ducts or ceiling air vent openings, the chances are that this is the problem.
Vacuum induced Equipment Leakage:
Most HVAC units create a significant interior vacuum. If there is a small hole or opening in the HVAC unit, the vacuum can pull rainwater inside the unit. Sometimes roof leakage occurs on brand new roof systems directly underneath HVAC units. When this happens, we conduct intensive water tests, to determine the source of the problem. In many cases, we find that the roof is not leaking. The HVAC unit is leaking internally.