What Does An Air Handler Do?
There are multiple components to an air conditioning and heating system. They all work together to keep you home comfortable throughout the year. Knowing how these different parts work together will help you understand the essential function of the HVAC equipment in your home.
Your air conditioning system consists of two parts, the air handler and the condensing unit. Your air handler is usually located in the attic, the garage or in a closet in your home.
In a split system, your compressor / condensing unit is a separate piece of equipment and is typically located outside of your house. If your AC system is a package unit then the air handler will be included as a part of the single packaged unit.
An AC system needs to move air through your home and the air handler performs this function. Within the air handler are the blower motor, the evaporator coils, and some of the HVAC system controls. Your air handler may be a horizontal flow or an up or down flow unit.
The air filter is usually located in the return register, however sometimes it can be found in a return duct or in the air handling unit itself. Be sure to ask your HVAC professional where the filter is located for your system so you can make sure it is replaced on a regular basis.
Filtering the air not only improves the air quality in your living space, but it is required for the efficient operation of your air handling unit (AHU). If air filters are not changed frequently, then dust and debris will build up and get pulled into the return. This inadequately filtered air will cause the evaporator coil to become clogged and your heat exchanger will operate at higher than optimal temperatures. This lack of proper filtration will cause the unit to operate less and less efficiently and can reduce the useful life of your unit.
The Air Handler’s Evaporator Coils
Your AC evaporator coils are used to transport the refrigerant. Together, the coil and refrigerant, during the heat exchange process, absorb the heat from the air passing through the coils. This absorbed heat causes the refrigerant inside of the evaporator coils to boil and change state. When the refrigerant enters the coils, it is mostly a liquid. When it reaches the end of the coils, it will have absorbed enough heat to change to a vapor.
There are two copper pipes on the outside of your air handler. One small uninsulated line, and one large insulated line. The large insulated line is the suction line. This line carries the vaporized refrigerant back to the compressor in your compressing unit. The smaller uninsulated line is called the liquid line. This line carries the liquid refrigerant from the condensing coils to the evaporator in your air handler. Whenever the unit is running, the large suction line should be cold and the smaller liquid line should be hot. The temperature of these two lines depends on how hot your house is and the ambient temperature outside.
Sometimes evaporator coils become blocked. This can happened when the coils are plugged with dirt, dust or debris, or if too many supply vents have been closed off in the house or if there is a collapsed duct in the duct system.
In order for the evaporator to work efficiently, the coils must be clear and have sufficient airflow. This is one of many reasons to have a clean air filter that can filter out particles before they reach the evaporator coils
The Air Handler’s Blower Fan Motor
The blower motor usually consists of several different components. It includes an electric motor and a cage, typically referred to as a squirrel cage. Most units have direct drive motors on the fan, but some have belt driven motors.
The only maintenance necessary on the blower is oiling the motor if it has oil ports or if it is belt driven be sure to check the condition of the belt.
The Air Handler’s Condensate Lines
If your air handler is located in the attic, it is important that the condensate line is periodically checked. The evaporator coil operates at a temperature less than dew point and it will condense the moisture from the air. The evaporator coil is designed to shed excess moisture into a drain pan.
Most drain pans have a ¾ inch PVC line attached that allows the excess moisture to drain safely to the outside of the house. Sometimes the PVC line becomes clogged with muck or algae and needs to be flushed out to clear the blockage. Any air handler located in an attic should have a secondary drain pan with a float switch installed. This float switch will shut off the unit if the secondary drain pan starts to overfill. No one wants to reinstall a ceiling because a float switch or secondary drain pan was not installed or checked for blockage. This kind of work needs to be done by a qualified HVAC professional.
Being a knowledgeable and conscientious homeowner can protect your home investment.
We recommend two Air Conditioning System Maintenance visits a year from an HVAC professional to help avoid costly repairs, increase your comfort level, and prolong the useful life of your air conditioning system.
Call Modern Service or Anderson Service today to find out about our comprehensive Air Conditioning Maintenance and Equipment Coverage Plans. Preventive maintenance now can save you a lot of money and hardship later.
