Fast Affordable Air recently inspected an air conditioning system in Las Vegas after signs of weak airflow and poor cooling were found. The project involved two important areas of the HVAC system. One was the flexible ductwork inside the attic. The other was the evaporator coil inside a rooftop Lennox unit.
The photos show a section of flexible duct that was squeezed between roof framing. They also show a thick layer of ice covering the evaporator coil. These problems can be connected. When an Air Conditioner cannot move enough warm indoor air across its cold coil, the coil temperature may drop below freezing. Moisture from the air then turns into ice.
A frozen coil should not be ignored. The ice blocks even more airflow and may place extra strain on the compressor, blower motor, and other Cooling components.
Inspecting the Attic Ductwork
The first part of this air conditioning repair focused on the attic. The flexible duct appeared compressed where it passed through the wooden roof framing.
Flexible duct is an insulated tube that carries heated or cooled air to rooms throughout a home. It works much like a large drinking straw. If the straw is squeezed, less air can pass through it. A crushed duct can have the same effect on a central AC system.
Restricted ductwork may cause several comfort problems:
- Weak airflow from one or more vents
- Rooms that stay warmer than the thermostat setting
- Longer Cooling cycles
- Higher electrical use
- Extra pressure on the blower motor
The duct was inspected for crushed sections, torn insulation, loose connections, and air leaks. A damaged section may need to be carefully repositioned and supported. If it cannot return to its proper round shape, replacement of that section may be the better repair.
The inside of the duct was also checked for damage and blockage. The inner liner should stay open and smooth so the blower can move air without fighting unnecessary resistance.
Finding Ice on the Evaporator Coil
The rooftop unit was opened so the technician could inspect its indoor Cooling section. The pictures show heavy ice covering a large part of the evaporator coil.
The evaporator coil is the cold metal part that removes heat from indoor air. It contains refrigerant and has many thin aluminum fins. These fins give the coil more surface area so it can absorb heat quickly.
Ice is not a sign that an AC is making “extra cold” air. It usually means something is wrong. Common causes include:
- A dirty air filter
- Restricted or damaged ductwork
- A dirty evaporator coil
- A weak blower motor
- Blocked return-air vents
- Incorrect refrigerant charge
- A restriction in the refrigerant system
The central Air Conditioning system must be turned off and allowed to thaw before the coil can be fully inspected. Trying to break the ice away can bend the soft metal fins or damage the refrigerant tubing. Fast Affordable Air also explains this process in its guide about what to do when an air conditioning system freezes.
Thawing and Cleaning the Coil
After the ice melted, the evaporator coil could be checked for dirt, bent fins, oil stains, and other signs of damage. Oil around a refrigerant tube can sometimes point to a leak, although proper testing is needed before confirming one.
The photographs show areas of flattened or uneven coil fins. A fin comb may be used to straighten lightly bent fins. A fin comb is a small HVAC tool that separates and lines up the thin metal strips. Severely damaged fins cannot always be returned to their original shape.
The coil surface and drain area should also be cleaned. Dirt acts like a blanket over the coil and makes it harder for heat to move into the refrigerant. Cleaning helps restore heat transfer and allows air to pass through the coil more freely.
Checking the Lennox Rooftop Unit
The final photo shows the open Lennox rooftop Heating and Cooling equipment. A rooftop package unit keeps the main Cooling parts, blower, electrical controls, and heating components inside one cabinet.
After addressing the visible airflow concerns, the technician would check the blower operation, electrical wiring, filter condition, temperature change, and refrigerant performance. Refrigerant is the fluid that carries heat from inside the building to the outdoors.
Adding refrigerant without completing these checks would not solve an airflow problem. A frozen coil can produce pressure readings that are misleading while ice is still present. The system must be thawed and moving the correct amount of air before refrigerant measurements can be judged properly.
Benefits of Restoring Proper Airflow
Correcting a squeezed duct and removing ice from the evaporator coil helps the Air Conditioner move cooled air more evenly through the home. Rooms can reach the thermostat setting faster, and the central Cooling system may not need to run as long.
Improved airflow can provide several benefits:
- Stronger airflow at the supply vents
- More even temperatures between rooms
- Less strain on the blower and compressor
- Better moisture removal
- Lower risk of the evaporator coil freezing again
- Less wasted electricity during long Cooling cycles
Las Vegas dust, long summer run times, and attic heat can make small airflow problems grow quickly. Regular AC maintenance in Las Vegas includes checking the filter, coil, blower, drains, electrical parts, and general Cooling performance. Fast Affordable Air provides HVAC repair and maintenance throughout Las Vegas, Henderson, North Las Vegas, and nearby Clark County communities.