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Refrigerants have two copper lines that connect the indoor evaporator coil and the outdoor heat pump. The suction line is the larger tube that has insulation. It carries cool gas under low pressure from the indoor evaporator to the outdoor compressor. The suction line is also called the return or the vapor line.
The other line is usually smaller and uninsulated. It carries hot liquid under high pressure from the condenser to the evaporator.
The suction line can freeze for many reasons. Read on to know the main ones.
Quick Summary: Why Is My AC Suction Line Freezing?
A frozen AC suction line is typically caused by restricted airflow (dirty air filters, closed vents, or a failing blower motor) or low refrigerant levels due to a copper line leak. Turning off your AC immediately prevents catastrophic compressor damage.
Is Your AC Unit Frozen Right Now?
Running a frozen air conditioner can ruin your compressor. Turn your thermostat to OFF, switch the fan to ON to melt the ice, and call Ideal Air for 24/7 emergency AC repair in Phoenix!
Airflow Problems
If the filter gets dirty, it blocks airflow to the evaporator coil. Without airflow, heat doesn’t get to the evaporator coil, and the refrigerant doesn’t boil. As a result, the pressure and the temperature will drop, causing the system to freeze.
If the filter you’re using is too restrictive, it can cause the same problem. In this case, scheduling timely AC filter replacement will restore proper airflow and keep your evaporator coil warm.
Also, the blower motor could stop working or run at a low speed due to worn-out bearings. An electrical problem could blow up the motor, or the board could fail to supply current. This problem reduces the amount of air getting to the evaporator coil. The longer you let the system work without the motor, the more ice will accumulate on the suction line. Anything that blocks airflow to the evaporator coil can cause the unit to freeze.
Low Refrigerant
A refrigerant is a compound that changes from gas to liquid and vice versa as it regulates temperature in the house. When the refrigerant absorbs heat from the house, it changes from low-pressure gas to high-pressure liquid. Then the high-pressure liquid travels outdoors, where a fan blows hot air. As a result, it turns back into a low-pressure gas.
The refrigerant’s volume remains at the same level throughout the air conditioner’s life unless there’s a leak. A leak causes the pressure inside the copper tubes to reduce. A reduction in pressure causes a drop in the refrigerant’s boiling point and temperature. Adding more refrigerant won’t help unless you find the leak and fix it. Our team uses advanced infrared diagnostics and electronic leak detectors to pinpoint hard-to-find copper line cracks.
When the refrigerant is low, its temperature at the beginning of the evaporator coil will be lower than the freezing point. The low temperature will cause the condensation inside the coil to freeze. Then, Ice builds on the coil and restricts airflow through the coil.
Without airflow to the coil, the refrigerant won’t absorb heat. So it will start to boil further in the coil, leading to more freezing, which continues up to the suction line.
Suspect a Refrigerant Leak?
Simply adding Freon won’t fix the root problem. Our certified technicians perform electronic leak detection and system recharges to restore your cooling power safely. Schedule Refrigerant Leak Detection & Recharge
Low Temperature
If the indoor temperature drops below 70F, the saturation temperature will also drop. And if it goes below 32F, the system will freeze. One reason why this might happen is if you set your thermostat too low. Most thermostats operate over 67F. If you set yours below that, it might cause freezing.
What You Should Do If Your Suction Line Freezes
If you notice frost on your suction line, check whether everything is running as it should. Check whether the motors are working and the fans are blowing air. If you don’t notice any problem, turn off the system to avoid causing further damage.
Remove the air filter and clean it to ensure the problem doesn’t result from blocked airflow. If the air filter is too restrictive or old, replace it. Keep in mind that many factors could cause the suction line to freeze. Sometimes the problem may be hard to detect. Instead of guessing what the problem is, contact our certified technicians for prompt AC troubleshooting and diagnostic service.
You can ask your HVAC professional to install a freeze stat. This device monitors the temperature of the heat exchanger. If the temperature falls slightly above freezing, the freeze stat initiates a protective action and keeps the suction line from freezing.
How to Keep Suction Line from Freezing
Most problems with the HVAC system occur due to a lack of regular maintenance. If you don’t maintain your HVAC system, it will become inefficient. As a result, it will take longer to achieve the temperature you want in your house. Inefficiencies will also cost you more in power bills.
In addition, lack of maintenance can accelerate the rate of wear and tear on the HVAC components. If serious damage occurs, you’d incur extra costs replacing those damaged components. To avoid unexpected summer breakdowns, protect your system with annual AC maintenance and tune-ups from Ideal Air.
Don’t Guess—Get Fast, Professional AC Repairs in Phoenix
Whether it’s a clogged filter, a blown blower motor, or a hidden refrigerant leak, Ideal Air Conditioning & Insulation is here to help. We inspect, diagnose, and repair frozen AC lines across Phoenix, Scottsdale, Mesa, and Tempe.