The main reason why your AC lines are freezing is because your evaporator coils are getting too cold. The evaporator coil is filled with refrigerant which cools the air in your HVAC system. When things are working properly the evaporator absorbs the heat from your air and provides a cooling effect.

What are the symptoms of a liquid line restriction?

Symptoms of a liquid line restriction include: Low evaporator (suction) pressure; High superheats; Higher-than-normal discharge temperatures; Low amp draw; Short-cycle on low-pressure control (LPC); Somewhat high discharge temperature; Low condensing (head) pressure; Low condenser split;.

Is the liquid line supposed to be cold?

When the system is operating, the large insulated suction line should be cold to the touch and sweating at any point where there is no insulation. The smaller uninsulated liquid line should be warm to the touch after the system has been operating for 10 or 15 minutes.

Why is my suction line freezing up?

Why Frost or Ice May Appear on an Air Conditioning Refrigerant Suction Line. Refrigerant charge level: Improper refrigerant charge (too low a charge of refrigerant in the A/C system can, for a while, lead to too-low temperatures in the coil which will then cause frost or ice build-up on the suction line.

How do I know if my liquid line filter drier is clogged?

Temperatures Drop Across the Filter Drier A symptom of a clogged liquid line filter drier is a temperature drop across the filter drier. Filter driers are typically shaped like a hot dog and are about the same diameter.

What are the most common causes of a restricted liquid line?

Liquid line restrictions can be caused by a restricted filter-drier, a restricted thermostatic expansion valve screen, a kinked liquid line, a bent lower condenser coil, or an oil-logged capillary tube. An evaporator that is starved of refrigerant will house a starved compressor and condenser as well.

Which one is the liquid line and suction line?

The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line. The smaller uninsulated line typically carries a warm liquid. It is most often called the liquid line.

Why is liquid line not warm?

the liquid line is high pressure not high heat. the whole point of the condenser is to take the very hot high pressure gas that comes out of the compressor and cool it down to a warm not-as-high pressure liquid as it exits the condenser. my liquid lines are typically only slightly warmer than ambient.

What should my liquid line temp be?

7. Also, note how much warmer the liquid line is than the outdoor temperature. It should be between 3°F and 20°F warmer than the outdoor temperature. If it is above or below that range, connect gauges.

Why is my high side line cold?

Most likely problem is a clogged drier. If one is not used on your system the next best guess is a clogged expansion valve. I would make sure they install a new drier during the repair.

Will low refrigerant cause freezing?

Low Refrigerant When the refrigerant is low, the coils will be too cold, causing them to freeze. Be aware that if your refrigerant levels cause the unit to freeze up, your coils can become damaged, which can then damage the compressor.

What would a thick frost buildup on the suction line to the compressor indicate?

Frost accumulation simply means the moisture in the air has reached its dew point temperature and has frozen into a crystalline structure. In many cases, the compressor, suction line, or a component in the suction line will be below freezing temperatures and will have frost accumulation while still operating normally.

Will suction line freeze if overcharged?

If the system is overcharged, part of the refrigerant cannot be evaporated, and the compressor will work with the refrigerant in liquid phase. It means that if the system is undercharged with refrigerant, the suction and discharge pressures are below the levels required for efficient operation.

How often should a liquid line drier be replaced?

All filter driers should be replaced every 2 years or by manufacturer’s recommendation. The Receiver Drier’s function in an automotive a/c system is to filter foreign material, remove moisture from refrigerant and to act as a reservoir to supply liquid refrigerant to the TX valve.

How do you know if you have a bad expansion valve?

Symptoms of a bad expansion valve Car AC system isn’t cooling enough or won’t cool at all. High side pressure is high. Air coming from vents is frosty. AC blows cold, then hot. AC kicks on and then immediately kicks off. Airflow drops dramatically from vents.

What is a common symptom of a severely restricted filter drier?

A starved evaporator from the liquid line (filter drier) restriction will cause high superheats. High compression ratios from the low evaporator pressure will cause high heat of compression, thus high discharge temperatures. This is assuming there’s still some mass flow rate of refrigerant through the system.

Why is my high side pressure going up and down?

What does higher than normal pressures on both sides mean? The two most common reasons for this condition is insufficient condenser airflow or an overcharged refrigerant system. Several conditions and components can affect the amount of airflow through the condenser coils.

Can freon lines get clogged?

Freon systems can develop clogged filters and valves. Because the refrigerant line is a closed line, it is unusual for the freon to carry many contaminants, but sometimes this occurs and the filter becomes full. An old filter may eventually create a clog in the lines if it captures too many particles.

Will a bad TXV cause coil to freeze?

Bad Thermal Expansion Valve Another reason for frozen lines in an AC unit is due to a faulty thermal expansion valve, also known as a TXV. This controls the flow of refrigerant through your AC unit. If this malfunctions then not enough refrigerant will pass through the system and the coils. That will cause a freeze up.

Do you insulate the suction or liquid line?

This is called the “suction” pipe and is typically the larger of the two pipes. There is no need to insulate the smaller, warmer copper pipe, often called the liquid line, because not insulating this line allows it to shed heat which is exactly what you are trying to do with an AC system.

What is the difference between suction line and discharge line?

The suction line connects the evaporator to the compressor, the discharge line connects the compressor to the condenser, and the liquid line connects the condenser to the expansion device.

What is the name of the refrigerant line leaving the compressor?

After the compressor compresses the refrigerant into a high pressure vapor, it removes it to the outlet called the “Discharge Line”. The “Discharge Line” leaves the compressor and runs to the inlet of the condenser.