When summer’s here, or really any time you want cool, dry air while driving, your car’s air conditioner (AC) is critical to your comfort and safety. Unfortunately, frozen AC lines can put a major kink in your road trip. Why are your car AC lines freezing up, and what you can do about it? Usually, AC is one of those forgotten systems that you never really think about until it stops working. Sometimes there can be worn or unmodified AC systems that function for years without a problem. On the other hand, if your car has been in an accident, has ever had any AC components removed or had any service done, the situation is ripe for frozen AC lines. What Causes Car AC Lines to Freeze Up? Really, the only thing that should be in your car’s AC system is refrigerant and oil. To keep these things inside and others — such as air, moisture and dirt — out, the pipes, hoses and seals are specially designed to maintain a tight seal. The problem of car AC lines freezing up is caused by moisture that has been introduced into the system.

At the expansion valve or fixed orifice tube, depending on the system, liquid refrigerant instantly expands into a gas, forcing the temperature to drop. Moisture in the system can freeze at that point, blocking refrigerant flow through the valve, and you’ll notice you have warm air coming out of the vents. As the valve warms up again, the ice melts and refrigerant flows, so you’ll get cool air again, but the cycle will continue. Generally, the only way that moisture can get into the AC is if the system is opened up or if you have a leak. thru the wall air conditioners/heatersIf there is a leak, air and moisture can be pulled in by vacuum on the low side of the system. miller ac unit reviewsAlso, any time that the AC system is opened, moisture can get in. window ac unit cover for winter

For example, if you use an R-134a top-off bottle to fill it up, a little moisture can get in when you open the valve cap and install the can. Similarly, if an accident breaks the system, such as the condenser or one of the lines, the open system can freely absorb water from the air. Normally, the receiver-dryer absorbs some of this moisture, but it only has so much capacity before it is saturated, leaving the rest to float about in the refrigerant stream. What Can You Do About Moisture in the System? If you notice your car AC lines freezing up, you have to get rid of the moisture that’s causing it, starting with a full leak check. Recover the refrigerant from the system and make any necessary repairs to parts such as O-rings, hoses, lines or evaporators. If the system has been opened for more than a few hours from an accident, damage or corrosion, the receiver-dryer absolutely must be replaced. It can become saturated when left exposed to the air. Alternatively, if the system has only been open a few minutes, during recovery and evacuation for engine repair, for example, you probably won’t have to replace it.

Evacuate the AC system for about 30 minutes to boil off any moisture in the lines. Finally, recharge the system with the proper quantities of refrigerant, oil and a little ultraviolet dye for future leak detection. For more information on car AC systems, chat with a knowledgeable expert at your local NAPA AUTO PARTS store. Photo courtesy of Pic Basement. So You Left Your Convertible Top Down In The Rain: Don't Panic! How to Apply Touch Up Paint Like a ProSometimes you may notice that your air conditioner freezes up after some time of operation. When this happens, the cool air will not be discharged properly and eventually a huge block of ice may built up on the evaporator coil. You will notice that there is less airflow coming from the air ventilation as ice began to clog the air movement. More condensation can be seen at the drain pan. At the same time, the room is no longer cool. This means that it is time to investigate the causes of this problem. Here are some possible causes.

When air flow or air circulation from the unit to the room and vice versa is restricted, the exhange of thermal energy between the air conditioner and the room is restricted. As a result, most of the cool air continues to stay around the evaporator coil and fins causing the temperature around them to drop. As a result, ice is formed and gradually more ice began to built up and eventually causes the air conditioner freezes up. Air Filters at the return air of the equipment must be serviced regularly by taking them down and wash with water and soap. These filters are used to trap dust and other bigger contaminants from going into the evaporator fins. Hence, cleaning them at least one or twice a month is highly recommended. In many cases, users will not even clean them once a year until this problem begin to surface.Evaporator coil and fins that are located after the air filters can also be clogged up due to dirty filters. In this case, you will need to clean them by using a spray type coil cleaner.

The other alternative is to get the technicians to come and take down the entire evaporator for cleaning. This will be more costly. Therefore, regular maintenance of the evaporator coil and air filters will go a long way in ensuring that your air conditioner continues to function properly.Fan or blower at the evaporator unit may not be functioning. When the unit is on, check that there is air flow coming out of the equipment. Otherwise, the fan may be damaged. In this case, the fan motor may have burnt or some loose connections may have occurred. Get a technician to check if this is the case.Check that there is no blockage of air around the evaporator by ensuring that things are not placed too near to the evaporator.One other step you can do is to check the set temperature of the air conditioner. Make sure that it is not set lower than 70 °F. When the refrigerant in the system is low due to leakage over time, there will be a decrease in the saturation point temperature of the system.

When this happens, it will take a lower temperature for all the refrigerant liquid that has been compressed by the compressor to become vapor in the evaporator. This means that the operating temperature of the cooling coils has now dropped compared to the original design. This lower temperature will cause moisture collected from the air to quickly becomes ice on the evaporator when the temperature goes below below 32 °F.These moisture that is supposed be cooled to a level which becomes water and drips to the condensate drainage pan is now stuck at the evaporator coils and fins forming ice around them. When this continues on, eventually a block of ice is formed on it. When you see the ice being formed on the evaporator, off the unit and wait for the ice to melt. It could take a few hours for all the ice to melt. A faster way is to on the air conditioner but using Fan mode. That means, only the fan is operating but the compressor is off. This will reduce the melting time of the ice but you will need to be around to monitor it as water may overflow and cause damage to your furniture or electrical items.