What to Do When Water Meets Your HVAC System

What to Do Whe n Water Meets Your HVAC System

Water that comes from HVAC leaks and flooding can cause serious damage to your system. It can get into your pipes, ductwork, furnace or air conditioner. Unchecked water can short your electrical components or can cause harmful corrosion.


Leaks and Clogs

HVAC leaks can cause damage to your system if they aren’t caught in time. Checking your indoor unit regularly can help detect early signs of an HVAC leak before it can cause more severe damage. Water pooling or running along the floor around your unit is a sign that there may be a leak or a clog that is causing a water problem.

Drain Lines

Water is a natural part of your air conditioning system. As hot, humid air is cooled, it creates condensation on the evaporator coil. The condensation then drips down into the condensate pan, which is emptied outside through a drain line. Sometimes the drain line becomes clogged or damaged, which will cause HVAC leaks. Drain lines should be checked monthly to ensure they are clear and draining properly.


Some HVAC systems use a condensate pump to drain off any condensation the system may create. Water accumulated from condensation within the system collects into a reservoir. Once the reservoir fills to a certain point, the pump switches on and pushes the water out through a drain line. Leaks in the pump can cause water to drip and pool in the system, causing damage to its parts. If water cannot drain out due to a clog, a safety relay will be activated and the system will shut down until the water is removed.


Flood water can be devastating. If your area experiences a flood, it can get into your building and wreak havoc inside your facility, possibly ruining equipment or parts of your interior. Your HVAC system can be very sensitive to flood water. Facilities that have experienced flooding or other emergencies should always have their HVAC system checked for damage that could make it unusable, or even dangerous.

Furnaces and Fuel Pipes

Water from floods, hurricanes or other natural disasters can damage your pipes. If your HVAC system runs on a fuel like natural gas, propane or oil, you will need to have the pipes checked for damage. All the supply lines, gauges and valves in and around the furnace will need to be inspected to ensure no water has seeped inside, which causes internal corrosion. Corrosion in your system can affect its performance, as well as increase the potential for fires or explosions. Waterdamaged furnaces and fuel lines will either need to be replaced or cleaned and decontaminated before resuming use.

Air Conditioners and Refrigerant Lines

The compressor and refrigerant lines of your air conditioner are outside, so even if water doesn’t run into your building during a flood, your AC system is still at risk. Flood water can get into the electrical components of your compressor and cause a short, which will keep your system from running until it is fixed. It can also disturb the refrigerant lines, causing them to leak or become disconnected. The air conditioner should be completely dried out and disinfected before allowing it to run after it has been in a flood. If any standing water remains after the flood it will have to be drained to keep your unit from corroding.

Insulation and Ductwork

Insulation in your HVAC system will have to be replaced after a flood, as well as the air filters. These items are known to trap moisture, dirt, debris and other contaminants that make them unsafe after suffering water damage. The air ducts and vents will need to be checked for any dirt or debris that got inside during the flood or storm. The aluminum walls of the ductwork should be thoroughly disinfected with a quality disinfectant.

Preventing Water Damage

Checking your system regularly is the best prevention for water damage. Drains should be checked for debris or dirt that can cause them to clog. Look at your condensate pan and your pump and make sure they are properly draining. If you know a storm is approaching that could cause water damage, try covering your outdoor unit and turning your system off to protect its electrical components. If you suspect water damage, always consult an HVAC professional to ensure your system is being safely handled.



Pub. 12/2016

The product statements contained herein are intended for informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness for a specific application or use. W. W. Grainger, Inc. does not guarantee the result of product operation or assume any liability for personal injury or property damage resulting from the use of such products.