September 2017 - HVAC Investigators

How hurricane force winds impact HVAC systems

The following article on “Windblown: How hurricane force winds impact HVAC systems”, written by Matt Livingston of HVAC Investigators, was originally published on Property Casualty 360.

The 2017 hurricane season has proven to be one for the record books, reminding everyone of the importance of being prepared to handle catastrophic losses. As demonstrated by Irma, the most dangerous aspect of a catastrophic hurricane is the accompanying storm surge along the coastline.

Equally important, the sheer wind speeds (and tornadoes spawned by the remnants of the storm) can wreak havoc hundreds of miles inland. These high winds can prove particularly damaging to roofs, siding, fences and HVAC systems.

Extensive damage caused by a hurricane-spawned tornado

And while many adjusters are experienced in assessing and estimating the costs to repair structural damage, diagnosing wind-driven damage to HVAC units can be particularly difficult.

A visual assessment of the extent of damages to an HVAC system is the first of many critical steps in reaching an appropriate scope of repairs (and associated settlement) to return the insured to pre-loss condition.

Condenser coil clogged with dirt and debris following high winds of a storm

Dust and debris-clogged condenser coils

High winds that accompany a hurricane often lead to excessive airborne dust and debris that will easily (in the best-case scenario) clog the aluminum fins of an HVAC system’s condenser coil. When the storm passes, property owners will often find the fins of the condenser coil packed with dirt, dust, grass, leaves and other small, lightweight objects from the surrounding environment.

When a condenser coil becomes clogged, the airflow through the unit is likewise restricted. This restriction reduces the potential heat transfer from the refrigerant to the ambient air, and in turn inhibits the HVAC system’s ability to adequately cool the conditioned space. It also causes the unit to work harder than under normal conditions, and slightly increases the system’s power consumption.

Fortunately, a clogged condenser coil is relatively easy to repair. Coils can be cleaned using condenser coil cleaner and a standard garden hose (a pressure washer should never be used to clean the condenser coil, as this can flatten the coil’s malleable aluminum fins). If performed correctly, this repair action can sufficiently restore a condensing unit to normal operation.

Microchannel coil damaged by wind-blown debris

Coil fins damaged by windblown debris

The condenser coil’s aluminum fins that surround the copper refrigerant tubing can be easily bent and flattened. If the strong winds of a hurricane or other storm send objects flying, they can easily dent the fins of the coil, similar to the effect of hailstones.

Once the fins are flattened, the airflow through the unit is restricted. As mentioned earlier, this condition can impact the system’s cooling capabilities, efficiency, and eventually, if left unrepaired for an extended period of time, the useful life of the system.

The potential repair actions for condenser coil fins flattened by wind-blown debris is similar to those used for repairing hail-damaged coils. Combing the coil’s fins should be considered as the first and most likely remedy. However, if the fins are torn, exceptionally brittle, or if the system utilizes a microchannel condenser coil (see example photo above), combing may not possible. In this scenario, the next repair action for wind-blown debris is the replacement of the condenser coil, an often ignored or forgotten repair option.

If the fins cannot be combed and the coil is no longer commercially available, the condensing unit may need to be replaced. Finally, if the replacement of the outdoor condensing unit leads to a technical or regulatory mismatch with the remaining equipment, full system replacement may be required.

The fins of this condensing unit were protected from the wind-blown debris; however, the corner panel was dented. The system was repaired by replacing the individual panel

Large foreign object impact to the condenser coil

Unlike smaller debris that simply clogs or dents the condenser coil, large, heavy objects picked up by strong winds can cause significant damage to an outdoor condensing unit. Hurricane force winds can send objects such as large branches, shallow-rooted trees or heavy building materials flying. If these objects make contact with the condensing unit, they may penetrate the refrigerant lines, damage multiple system components or even crush the system in its entirety.

The extent to which a system is damaged depends not only on the weight and speed of the flying object, but also on the construction of the condensing unit. Of course, the severity of system damage and availability of replacement parts will dictate if the unit is repairable.

Condensing unit damaged by heavy, wind-blown object

Displaced Equipment

During a hurricane, 160-mile-per-hour winds can take a toll on HVAC equipment. While the typical residential condensing unit weighs between 150 and 200 pounds, it can still be easily blown askew from its position on the rooftop or ground pad. Following tornadoes and hurricanes, it is common to see equipment displacement ranging from minor shifts to those that are completely blown over.

Condensing unit blown off of pad by high winds

Blown away

Once a condensing unit has shifted on the pad, it is important to assess whether or not the refrigerant lineset has been breached. If so, moisture and contaminants may have entered the refrigerant loop and can cause significant damage to the compressor. If the unit was blown over, the condenser coil and the fan assembly may also be damaged. Depending on the extent of the damage, repairs may still be possible, up to and including the replacement of the condensing unit.

Fortunately, in hurricane-prone areas such as Florida, building code regulations often require that all outdoor mechanical equipment exposed to wind be able to withstand wind pressures, or be securely fastened to the ground/rooftop (Florida Building Code, Mechanical Sec 301.15).

The required wind resistance depends on both the specific county and usually, the zone within that county. As an example, in Miami-Dade County Risk I, mechanical equipment is required to be able to withstand gusts of wind for three seconds at speeds of up to 165 mph (Florida Building Code, Sec 1620.2).

Significant damage to a condensing unit during a hurricane

As with any property claim, it is important for adjusters to consider all options before coming to a settlement decision following a hurricane or tropical storm, and a thorough visual inspection is the first critical step along the settlement path.

Although devastating, wind-damaged HVAC systems are often repairable, if objectively evaluated by a licensed professional. Most HVAC configurations include both outdoor and indoor equipment, offering frequent opportunities to return the system to pre-loss condition via simple and straightforward repairs.

For information on water and lightning damage accompanying hurricane claims, you can access our adjuster toolkit for hurricane claims. You can also review a labeled split system diagram and a labeled packaged unit diagram, to assist in identifying components and their susceptibility to wind and foreign object impact damage.

Identifying water-damaged HVAC systems after a hurricane

The following article on “Identifying water-damaged HVAC systems after a hurricane”, written by Matt Livingston of HVAC Investigators, was originally published on Property Casualty 360.

As the floodwaters recede across the Gulf Coast following Hurricane Harvey, the arduous process of claims investigation begins to unfold. CAT adjusters from across the country are travelling to the impacted areas to assess property losses and assist insurance carriers in reaching accurate settlements.

For many adjusters, one of the most difficult property components to assess is the HVAC system. HVAC equipment is simply too expensive to indiscriminately write replacement estimates, and accurate pricing and availability is also difficult for adjusters to access. Moreover, determining if the equipment is damaged is itself a difficult task – it’s not always a matter of just turning on the system to determine whether or not it works. Many of the properties are still without power, and once restored, diagnosis may prove difficult without first determining the full extent of potential damages.

This illustration depicts the amount of water that can accumulate before affecting a ground-mounted condensing unit.

Outdoor equipment inspection

The first component to be assessed for damage is the outdoor condensing unit, typically located on the ground or on the roof of the property. If the unit is located on the roof, it is unlikely that it suffered any damage from floodwaters, although it should still be checked for any additional storm damage.

Condensing units are designed to withstand the elements, but muddy, rushing floodwaters can impact ground-mounted systems and lead to repair actions ranging from a simple coil cleaning to a full system replacement. The water can typically rise to the compressor terminals before causing significant damage, as seen in the illustration here.

When assessing the outdoor condensing unit, here are a few things to look for:

Check for dirt and debris stuck in the condenser coil fins. Where the debris ends typically indicates how high the floodwaters rose on the unit.
Water lines on the system’s back panel, its electrical compartment, or an adjacent building wall also provide clues as to how much of the condensing unit was exposed.
Based on how high the water rose, determine which components the water may have compromised, such as the compressor, electrical compartment and fan motor.
Look to see if the condensing unit shifted on the pad. If shifting did occur, check the copper lineset for any breaks or kinks. A breached lineset may have allowed contaminates to enter the refrigerant loop, which could damage the compressor and other components.

Water line on condensing unit indicating how high the floodwaters rose

Indoor equipment inspection

Depending on the type of HVAC system, an indoor furnace or air handler may also be present. The location and orientation of the indoor equipment will influence the amount of damage the unit sustained. A horizontal furnace mounted in the crawlspace is typically more vulnerable to water damage than a vertical furnace in a lower floor utility closet or basement (unless the basement was completely flooded). Furnaces or air handlers mounted in the attic or on a second floor, on the other hand, may have no damage whatsoever.

How various water levels can impact a horizontally-mounted furnace in a crawlspace

Water levels in horizontal systems

A horizontal furnace or air handler in a crawlspace is particularly susceptible to water damage. The amount of water that can inundate the crawlspace before impacting the equipment depends on how high the system is mounted (sometimes dictated by building code) above the ground. Once the water reaches the system, however, it will likely suffer significant damage, as seen in the illustration here.

How a vertically-mounted furnace can be affected by floodwaters.

Vertically mounted units

A vertically mounted furnace may be more protected from water damage. This orientation will not typically sustain significant damage until the water reaches the burner compartment (found in the middle of the unit, several inches above ground level), as seen in the illustration here.

Here are a few things to look for when assessing the indoor equipment for floodwater damage:

Look for a water line on the outside of the furnace/air handler, on rigid ductwork or on an adjacent wall.
Check the control board for water damage. Often (depending on when it was printed), the board’s writing will “bleed” when exposed to water, providing a useful clue in estimating the water’s reach.
Examine any sheet metal ductwork for premature rusting or corrosion.
Flex ductwork will sag and duct board will swell after getting wet, indicating floodwater contact.
The insulation on the inside of the blower compartment will often be damaged by the water.

Water line on furnace indicating how high the floodwaters rose

Once you have determined (both indoor and outdoor) how much water damage an HVAC system sustained, you can begin the process of establishing a proper scope of repairs. It is important to keep in mind that even in severe flood scenarios it is rare that a full system replacement is necessary. In many cases, individual components can be replaced and systems can be cleaned to achieve pre-loss condition. Remember, a portion of the system (or in the case of packaged units, the full system) may be located high enough on the property to avoid the floodwaters from the hurricane, and could thus significantly influence the required scope of repairs.

For information on wind and lightning damage accompanying hurricane claims, you can access our adjuster toolkit for hurricane claims. You can also review a labeled split system diagram and a labeled packaged unit diagram, to assist in identifying components and their susceptibility to floodwater damage.