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Protecting Your HVAC from Storms

April 15, 2017

In Middle Tennessee, destructive storms are not only the norm, but becoming more frequent.  Tennessee has already had more tornadoes so far this year than all of last year or the year before!  Your HVAC system is the single most costly system in your home – not just in yearly maintenance and energy costs, but also when it comes to replacing it.  Although you cannot prevent tornadoes, snow/ice storms, wind, hail, rain, lightening, and floods, you can help prevent some of the associated HVAC-related repair or replacement costs by taking a few precautions.  This post will provide useful tips for protecting your HVAC before and during a storm, as well as tips for dealing with some common problems after the storm has passed.

Before the Storm

In the spring (before “tornado season”) and in the fall (before snow and ice hit), go through this checklist:

Anchor the outdoor unit. Your outside AC equipment should be installed on a level, raised, pad.  Ensure water does not pool near the unit during a heavy rain by ensuring downspouts are routed far away from the unit, that there is an adequate gravel border around the pad, and the land is sloped for optimal drainage.

Remove projectiles.  In Nashville, it is not uncommon to find your neighbor’s lawn furniture blown into your yard after a storm, or to have tree limbs fall on your property.  Secure or store any loose items from your yard such as lawn furniture or grills that can be blown into the outdoor unit. Remove or trim all bushes, trees and dead branches that could fall onto the unit in a storm.

Install hail guards.  It has become commonplace for Tennessee to get hail along with rain and winds. Impacts from hail can be particularly damaging to the fins and refrigerant coil of the condensing unit.  Hail guards are thick metal “netting” that can stay in place year-round and still allow operation of the system (unlike covers!). They can be installed with hinges so they can be easily removed for servicing the unit.

Prevent electrical shorts.  Be sure to cover and secure any wires between the outdoor unit and the house so that they are not exposed.  If they get wet or frayed, they could short out!  Over time, even insulated wires can deteriorate by normal sun and temperature changes.  Styrofoam “noodles” with hollowed out centers for wrapping around wires) are one way to keep the wires protected, and they can easily be cut to any length and taped shut with weather-proof tape.

Install surge suppression.  Storms often cause electrical disturbances or fluctuations in power (so-called “surges”).  To protect your HVAC equipment, install a high-quality surge protector that will automatically turn off your HVAC system to protect it from damage if there’s a spike in the line voltage. Consult an electrician to install a surge protector at the circuit breaker box. This can prevent expensive repairs due to blown fuses, burnt capacitors, and fried compressors.

Install a sump pump, if necessary.  Basement floods are a major cause of HVAC system problems. Protect your equipment by installing a sump pump to automatically detect and remove water. Consult a water-proofing professional to address your foundation and basement issues.  Keeping the basement and crawlspaces dry will also prevent mold from being drawn into the ductwork.

During a Storm

With all the weather alerts provided by various media – on TV, on our phones, and audible sirens – we often have at least a few minutes advance notice of impending destructive weather.  First and foremost, you need to seek shelter, but if time allows here are some steps you can take to prevent HVAC equipment damage:

  • Turn it off.  Avoid using your HVAC during a storm. Power surges might cause damage to its electronics. Shut off your heating and cooling system at the thermostat first, then at the circuit breaker. This ensures your AC or furnace will not inadvertently turn on during a storm, possibly damaging the coils or fins.
  • Cover it.  Most outdoor condensing units are not sheltered from the weather. Air conditioner covers (usually made of heavy canvas or vinyl) are relatively cheap, available online, and offer good protection from hail storms and snow and ice.  However, the system must remain off while it is covered.  Prior to turning your equipment back on after the storm, you must remember to remove the cover and any debris that has gathered on or around it.  Tip:  Do not use a tarp or other protective cover that completely covers the unit, as it can cause moisture to build up inside the unit or attract animals seeking shelter.  Leave at least a foot of space around the bottom of the unit to allow it to breathe.

After the Storm has Passed

After the storm has passed, do not immediately switch the HVAC unit back on!  First, inspect your outdoor condensing unit for any signs of damage.  Look for cracks, impacts from hail or flying debris, harm to any of the refrigerant or electrical lines, and remove any debris that has fallen in or around the unit.  Check if there has been any movement or shifting of the unit off the pad, or if flooding and erosion has now caused the system to be un-level.  If you see any of this, call a licensed professional to inspect your system before turning it back on. If any power lines have fallen nearby your unit, do not approach the HVAC unit or turn it on until they are cleared.

But, What if…?

The more typical scenario is that the storm caused a power outage, and when the power was restored, the HVAC did not come back on as expected.  If this is the case, then after visually inspecting the inside and outside units and seeing no damage, follow these steps:

  1. Check the thermostat, to be sure it has power. Turn the thermostat off and then back on, wait a couple of minutes, then change the temperature to a setting that would normally trigger the unit to come on, and give it a few minutes to cycle.  If the unit still does not come on, then turn it off at the thermostat and proceed with step 2.
  2. Check the circuit breaker.  If it has been tripped, flip it off, wait a minute, and flip it back on again.  Then re-try step 1.  If the unit comes on for a short period and then goes off again, or if the circuit breaker is immediately tripped again, proceed to step 3.
  3. Call an HVAC service professional.  If there is evidence of a melted or burned fuse at the fuse box, contact a licensed electrical professional.  In either case, leave the unit turned off until help arrives.

In the event there has been visible damage or the unit has been hit by lightning, make photos of the damaged unit for your insurance company. Most insurance policies cover power surge damage to HVAC units and their associated electronics (thermostat, etc.).  Also, if there is any question, contact an HVAC professional so that something small does not turn into a major expense.  For example, replacing a damaged capacitor is an inexpensive repair but if it is ignored, it can lead to a failed compressor which is an extremely costly replacement.

Whether you need help preparing for a storm or dealing with its aftermath, know you can rely on Interstate AC Service to find the most affordable, effective way to deal with the problem.  If you live in the Nashville or surrounding area, call on us at (615) 832-8500.