HVAC Units and Seasonal Changes

The summer season in Alabama is classified as a sub-tropical environment. Humidity and temperatures are high. People reach for that thermostat on the wall and turn the dial down to condition the air.

It is a bit counter-intuitive to think that something could freeze over when it is so hot outside.  Because most folks don’t understand the structure and function of an HVAC system, they find themselves at a complete loss when simply turning the thermostat down doesn’t do the trick. It is important to understand the causes of coil freeze so actions may be taken to prevent it from forming at the most inconvenient times!


HVAC Air Flow Is Blocked

The HVAC system installed in your home or business is a closed system. That is to say, once air has entered into it, that air is contained within a system of ducts, vents, and mechanicals that change the quality of the air. One of the first things to look for if you have frozen coils is whether or not the air flow is being impeded anywhere. When the air flow is restricted or blocked altogether, there isn’t enough air flowing through the system to prevent condensate from building up on the coil and freezing.

Two Things to Do:
  • Move furniture, boxes, objects from in front of vents usually located in each wall of each room.

  • Check the air filter and ensure it is not clogged. If clogged, clean it or replace it.

Two Steps to Take:
  • If you find your air conditioner is frozen, the first thing to do is move the thermostat to the off position to allow the defrosting process to start.

  • The next step is to turn on the fan. Let it work for at least an hour depending on the thickness of the ice and the outside ambient temperature.

HVAC Refrigerant is Leaking

Firstly, refrigerant does not get used up like the oil in your car. When your HVAC unit was installed, the system was filled or “charged” with an appropriate amount of refrigerant for the technology being installed. With regular maintenance and manufactured parts functioning within warranty, the unit’s level of refrigerant should remain constant.

However, after a period of use, the system may develop cracks and holes due to age and excessive demand. Metal coils can wear over time and develop small holes. Contaminants also build up combined with dirt and grime. These factors come together to cause a deterioration of the metals, alloys, and plastics used for the manufacturing of various parts.  These holes allow the refrigerant to gradually escape causing your system to become less effective in removing the hot air from your inside environment.


If Refrigerant Leaks Are Ignored:

You can have system damage caused from the thermostat constantly sending demand signals to the system to try to reach “set point.” Your HVAC system will operate longer and have longer cycles placing an excessive demand on the AC parts. These parts will eventually breakdown due to work overload times or place excessive internal pressure that can damage vapor compression units (compressors). This over demand placed on your HVAC unit will result in a higher expenditure on energy.

Two Mistakes Made by Homeowners:
  • An attempt is made to repair the leak with a retail purchase of an alloy, glue, tape, or sealant that eventually fails again because the correct product was not used for the repair or the extent of damage was not comprehended.

  • Folks simply charge the system back up again. Because the actual cause of the leak has not been determined or repaired, the system will just have other kinds of breakdowns due to an excessive on demand workload. Also, the refrigerant will begin leaking out again.

Two Things to Do:
  • Contact a heating and air conditioning company to have your HVAC unit diagnosed by a qualified HVAC service person. The service technician will be equipped with the latest inspection and leak detection technology.

  • If your system is old or no longer the correct size due to environmental changes, failure of parts within the system, additional structures built on to your home, leaking ducts or leaks elsewhere in the dwelling, or simply a misdiagnosis of the original sizing demands of your location, the coil may need to be replaced.

Regular Maintenance

A detailed and consistent maintenance schedule for your HVAC unit will serve it and your wallet well. The system should be analyzed, performance checked, refrigerant levels evaluated, and cleaned once or twice per year depending on your service needs and local climate. Typically, a technician will do an inspection of parts, wiring & electrical evaluation, cleaning of ducts, pans, and lines, and will clean the coils and fans.