How does an HVAC system work? Contrary to popular belief HVAC system's do not create cold air, HVAC systems take warm air from inside and exhaust the warm air outside. HVAC system's have two coils, the indoor evaporator coil and the exterior condenser coil. The basics of how the average HVAC system works are as follows:

- Refrigerant enters the evaporator coil in a low temp, low pressure state, as it flows through the coil air from the home is being blown across the coil, the refrigerant pulls heat from the air.

-The refrigerant flows through the suction line where it then enters the compressor, the compressor compresses the refrigerant into a high temp and high pressure gas.

- The refrigerant then flows into the condenser coil at a temperature that is above outdoor air temps, a fan blows across the condenser coil, this cools the refrigerant down slightly and moves the heat to the outdoors.

-The refrigerant is now a high temp liquid, as the refrigerant flows back towards the evaporator coil it enters an expansion device, this cools the refrigerant back down to around 20 degrees F before repeating the process again.

Now that we have an idea of how the system removes heat from the home, lets talk about another function of the unit, removing moisture from the air. As warm house air flows over the evaporator coil moisture is pulled from the air and collected in a condensate tray. This condensate must be disposed of properly either by a drain that flows by gravity, or a pump if a gravity drain is not possible. Improper discharge locations include flowing down the homes exterior wall, into a floor slab with no drain, or into any main plumbing stacks.

For Unit's located in attics a secondary drain pain under the unit must be provided. This secondary pan needs either a secondary condensate drain that discharges to a conspicuous location, or a high water alarm. All condensate drains must be trapped to prevent air from entering the drain line, this maintains a pressure balance within the system.

Here are some helpful tips to keep your HVAC unit functioning properly:

-Change filters on a bi-monthly basis.

-Have the unit serviced annually.

-Periodically inspect your secondary condensate discharge location if you have an attic unit.

-Ensure your exterior unit is clean and free from debris, the outdoor unit needs around 2-3 feet of clearance on all sides and the top to properly get rid of heat.

-Periodically inspect your main condensate line and flush the line if necessary.

Here is a diagram of how the average HVAC system works: