Fast Affordable Air recently inspected an attic-mounted air conditioning system that was not providing enough cold air. The project involved checking the indoor equipment, evaporator coil, drain pan, duct connections, electrical parts, refrigerant pressures, and air temperature at the ceiling vent.
The pictures showed several warning signs that could explain the weak cooling. These included heavy frost on the indoor coil, standing water inside the drain pan, openings around the air handler, and air coming from a supply vent at about 74.3°F.
Starting With the Attic Air Handler
The first step was inspecting the attic air handler and the connections around it. An air handler is the indoor part of an HVAC system that moves cooled air through the ductwork and into the rooms.
One picture shows a round duct opening connected to the metal cabinet. The edges around this connection were checked for gaps and loose sealing material. Even a small opening can allow cooled air to escape into the attic instead of reaching the living area.
Air leaks can also pull hot, dusty attic air into the central air conditioning system. This makes the equipment work longer and can reduce indoor comfort.
Standing Water Inside the Drain Pan
Water was found inside the bottom pan near the evaporator coil. This pan is designed to catch condensation. Condensation is the water created when warm, moist air passes over a cold surface.
A small amount of water may be normal while the Air Conditioner is running. A large puddle is not. Water can collect when the drain line is clogged, the drain pan is damaged, or a frozen coil begins to melt.
The drain line and pan should be cleared and inspected so water can leave the system correctly. This helps protect the ceiling, insulation, wood framing, and nearby electrical parts from water damage.
Heavy Frost on the Evaporator Coil
The evaporator coil in the pictures had a thick layer of frost across its metal fins. The evaporator coil is the part that absorbs heat from the indoor air. Air must move freely through the thin fins for the cooling process to work.
When the coil freezes, air cannot pass through it properly. The home may feel warm even though the central AC keeps running. The system may also use more electricity because it is working without producing enough cooling.
A frozen coil can be caused by weak airflow, a dirty filter, blocked ductwork, a dirty coil, a blower problem, or low refrigerant. The ice must be allowed to melt before accurate testing and cleaning can be completed.
After the coil is fully thawed, the fins can be inspected for dirt or damage. The filter, blower, return opening, supply ducts, and refrigerant system should also be checked to find the reason the ice formed.
Checking the Ductwork and Cabinet Seams
The attic pictures also show openings and worn sealing material around the metal plenum and refrigerant lines. A plenum is a large metal box that receives air from the HVAC unit before sending it into the ducts.
Cracks and gaps around the plenum can waste cooled air. Proper HVAC-rated sealant or approved foil tape can be used to close these openings. Regular cloth duct tape should not be used because attic heat can cause it to dry out and peel away.
Sealing these areas can provide stronger airflow at the vents, steadier room temperatures, and less cooling loss inside the attic.
More information about attic system inspections and duct sealing is available in Fast Affordable Air’s attic air handler and duct sealing project guide .
Inspecting the Refrigerant Lines
The copper refrigerant lines entering the indoor cabinet were inspected for damaged insulation, oily marks, frost, and loose connections. Refrigerant is the material that carries heat from inside the home to the outdoor unit.
Damaged insulation can allow heat from the attic to enter the cold suction line. This may reduce efficiency and create extra condensation around the pipe.
The technician connected a manifold gauge set to check the system pressures. A manifold gauge is a tool that measures the pressure on the low and high sides of the Air Conditioning system.
Pressure readings must be compared with the outdoor temperature, indoor temperature, equipment information, airflow, and refrigerant type. Pressure alone does not prove that a system is properly charged.
Checking the AC Pro Dual-Run Capacitor
The electrical inspection included an AC Pro dual-run capacitor rated at 45+5 microfarads. A microfarad, shown as µF, is the measurement used to rate a capacitor.
A dual-run capacitor supports two parts inside the outdoor unit. The 45 µF side normally supports the compressor, while the 5 µF side supports the condenser fan motor.
The capacitor should be tested with a meter and compared with its printed rating. A weak capacitor can cause hard starting, slow fan operation, humming, overheating, or an Air Conditioner that will not start.
Using a correctly rated replacement is important. A capacitor with the wrong rating can damage the compressor or fan motor. The AC Pro component shown is marked with a tolerance of plus or minus five percent, which tells the technician how close its test result should be to the listed rating.
Measuring the Air at the Ceiling Vent
A General infrared thermometer was used at a ceiling supply vent. The display showed about 74.3°F. A supply vent is the grille that sends conditioned air into a room.
This reading suggested that the system was not delivering very cold air at that moment. However, one vent reading does not tell the whole story. The technician also needs to measure the air entering the system at the return grille.
The difference between the return temperature and supply temperature is called the temperature split. For example, if 80°F air enters the return and 60°F air leaves the supply vent, the temperature split is 20 degrees.
After correcting the airflow, drainage, electrical, and refrigerant-related concerns, the temperature split should be checked again to confirm that the Cooling system is removing heat correctly.
Benefits of Correcting These Problems
- Stronger airflow from the supply vents
- Less cooled air escaping into the attic
- Lower risk of water damage around the indoor unit
- Less ice forming on the evaporator coil
- Reduced strain on the compressor and blower motor
- More even temperatures throughout the home
- Better energy use during the Las Vegas cooling season
Fast Affordable Air provides air conditioning repair in Las Vegas , Henderson, North Las Vegas, and surrounding areas of Clark County. Preventive services are also explained on the company’s AC maintenance page and Air Conditioning tune-up page .
