Can Heavy Rain Damage Your HVAC System?
Potential Weather-Related A/C Problems
Storm Damage. While rain won't probably damage your air conditioning unit, high winds that accompany it may cause falling objects like tree branches that damage the condenser fan grille or deposit leaves and other debris inside. Inspect the exterior and interior of the unit after any severe storm.
Flooding. Even though several inches of rainfall from a thunderstorm shouldn’t threaten your A/C, deep standing water from localized flooding could affect it. Normally, as long as flood waters don’t exceed around 15 inches in depth, the moving parts and electrical components of the outdoor unit should weather the storm. If you experience more severe flooding, have your HVAC contractor check out the unit before your restart it.
Internal corrosion. Many homeowners will cover the outdoor component of their A/C for the winter. If you decide to do so, select a commercially available cover with proper ventilation openings. Wrapping the unit in plastic for an air-tight enclosure subjects internal components to an environment of continuous moisture for months. Unlike rainfall that dries up with ventilation, trapped condensation will rot wiring and rubber as well as corrode metal parts.