Flooded Commercial HVAC Units: Fixing HVAC Units After Flooding

The U.S. is home to millions of successful businesses that hope for the best. Unfortunately, Mother Nature may have other plans. Flooding has become a common threat, and recent reports suggest it will only grow worse. According to Pacific Standard magazine, changing atmospheric conditions has led to an increase in the frequency and severity of extreme flooding. As a result, floods are likely to be larger and last longer than those of the past. Even with the best intentions concerning your facility readiness plan, Facility Managers may face flooded commercial HVAC units. Although it might seem like the process for remedying flooded units is to let them dry out, it is much more involved. Facility management professionals should follow these steps for minimizing risk and ensuring systems function as expected, says FacilitiesNet.

Shut Down Power to the HVAC System

Now, let's address the elephant in the room. It is essential to shut down power to the HVAC unit as soon as possible. For vacant facilities, it may be wise to power down the unit before a storm's arrival, which will minimize damage to the computer and electrical components. If the unit was left on, shut it down before any servicing after the flood.

Inspect Flooded Commercial HVAC Units for Debris and Damage

After an event, the unit will take on water. This may be true of rooftop units as well that succumbed to excessive rainfall or flooding on roofs where drainage could not keep up with precipitation rates. Inspect all units for signs of damage and flooding. Also, remove debris from the ducts and units. For all repairs requiring technical skills, contact an appropriate field service technician. Even if you know how to repair the unit yourself, self-repairs may void warranties and insurance liability.


Before beginning the cleaning process, seal off the affected area. This is especially true for connected HVAC systems that serve multiple parts of a building. Next, it is time to clean the unit. This includes physically wiping away all mud and other materials from the unit. Any components, such as filters, capable of absorbing flood water will need replacement as well. Also, always wear appropriate gear, including goggles, face masks, and gloves when working in affected areas.


Disinfecting is best achieved by cleaning with bleach and following with a clean water rinse. Furthermore, work from clean-to-dry, eliminating the risk of recontamination. Remember, flood waters may contain numerous bacteria and pathogens, which may be aerosolized within the HVAC unit. Bleach will kill them.

Bring the System Back Online

Depending on precautionary steps taken, such as shutting down automatic HVAC controls prior to a storm's arrival, begin the process of bringing the system back online. It may be necessary to restore power and reset system functions to manual.

Run HVAC System Continuous to Flush All Air

Facilities Managers will next run the system continuously for a period of no less than 48 hours to flush out all contaminated air and identify any possible problems.

Perform Additional Health and Safety Checks

Additional health and safety checks include inspecting the area again for the presence of gases or chemicals that may harm building occupants and equipment. Remember, humidity can devastate electronic equipment.

Avoid the Hassle by Letting an Emergency Facility Services Provider Handle the Work

Restoring the function of flooded commercial HVAC units is not a small task. Depending on the severity of flooding and damage to the unit, repairs may take days, if not weeks to complete. Think about it. Something may have been swimming around in your unit. Do you want to take the risk of running it without professional help? Instead of trying to go it alone, minimize disruption by working with an expert provider of emergency facility services. Also, establish such relationships well in advance before the rainy season ever arrives.

Eric Crabb

Eric Crabb