< 1 2 34 > 2 posts, read 65,903 times Originally Posted by GAwareagles51 In the middle of record setting heat (if not otherwise) set your thermostat higher than 72 What does this sound like to you. Sounds like you need to raise the thermostat a few degrees. Could be a couple of different issues. It could be airflow has dropped from a clogged coil, bad fan motor, clogged fan blades or a combination of all three. It also could just be you're using the wrong filter. Are you using a pleated type "high efficiency" filter or one of those hog hair filters? You can try taking the filter out and see if that stops the freezing (make sure the coil is completely thawed though before you try this). If that solves your problem then go buy some of the el cheapo air filters which aren't restrictive but do allow more debris to get by them. It also could be low on refrigerant. It could also be a combination of all of the above. Without more information, which you're most likely not going to have access to, we can't help you any more than that.

you'll need to call a technician. Assuming this is a 10 SEER system or less the Approach for the evaporator coil should be 35� below indoor ambient. That means at 72�F the evaporator should be operating at around 37�F. The "approach method" is the expected difference in a properly operating HVAC system between condensing/evaporating saturation points and the indoor/outdoor ambient air temperature. That should mean a higher heat load on the evaporator (unless there is an airflow problem) which wouldn't cause freezing issues. For the record, the average residential system would hold less than four pounds, so that was pretty close to empty. My first guess is a clogged air filter, this is the most common cause. If you compare a new air filter with old one, you'll notice that the new one is white and the used one is off white in color. This is when you should replace it. you should never allow it to get so clogged that it's any darker than off white in color.

If your filter is OK, my next guess is the coil is clogged with dirt caused by not replacing the filter often enough. 43,216 posts, read 43,024,441 times If your filter and coil are not blocked then Your low on freon. Before you ask here is why. The pressure in the suction line is kept at a level that keeps the evaporator from freezing. If your low on freon the pressure drops in the line bringing the temperature below freezing causing it to ice from the evaporator right back to the compressor. While the line runs colder you actually lost capacity from your system from the loss of refrigerant. Loose anymore and the iceing will stop and the air coming out will start to be warmA very large number of homeowners will turn their air conditioner on this summer and experience the same thing: the outdoor unit kicks on, the indoor fan blows air, but the air coming out of the vents is not “blowing cold”.  While there can be a number of different causes, a large percentage of units are low on refrigerant.

Years ago, adding a pound or two of refrigerant was an inexpensive way to get you by.  In fact, this became part of a yearly maintenance for some.  Today, Bill Brown with Paramount Heating & Air Conditioning, in Worthington, OH explains why the choice to add refrigerant isn’t as simple today.ac unit assistanceIf your system is low on refrigerant, it is because you have a leak. green hvac unitsRefrigeration systems are completely sealed and they do not “use” refrigerant but rather “re-use” it.  car air conditioner repair manualThe magic of the refrigeration cycle is that it allows 5 lbs of refrigerant to cool your home for 20 years, providing it is well installed, maintained, and doesn’t lose its refrigerant charge.As an air conditioning contractor, once we inform a homeowner that their system is low, we hear a few common questions and would like to address them:Should I just add refrigerant today?

There are three things to consider before adding refrigerant to a system:  System age, refrigerant type, and how much refrigerant is needed.System Age- If  your air conditioner is less than 10 years old, and well maintained, it should have a good deal of life left.  Time spent locating and repairing a leak, plus a recharge could yield 5-10 more years of operation.  If the system is beyond 10 years, it may be a better investment replacing the system. The new system will have a 10 year warranty, the new refrigerant, R-410a or “Puron”, and, of course, no leaks.Refrigerant Type- Most systems installed before 2008 have R-22 refrigerant. This type of refrigerant has been marked for phase out due to that fact that it has ozone depleting characteristics.  After January 2010, HVAC manufacturers could not ship units with R-22.  In 2020, refrigerant manufacturers like Honeywell and Dupont will not be able to make any new R-22 for service, so you can expect prices to be astronomical by that point, perhaps hundreds of dollars per pound. 

If your system contains R-22, prices can be more than $75 per pound today.  Systems installed as early as 2004 may have R-410a refrigerant.  Since HVAC manufacturers have standardized on this type, the prices are much lower per pound than R-22.  For the most part, if your system has the newer refrigerant, it is also new enough that locating a leak, repairing, and recharging is probably a good investment.How low is your system?- The majority of residential systems contain between 4-7 lbs of refrigerant, however some contain as much as 15 lbs.  Typically when we arrive to a customer’s home who is complaining of reduced cooling, their system charge is a ½ of the total charge or lower.If the system is completely out of refrigerant, you either have had a leak for a long time, or have a major leak.  If you have the old R-22 refrigerant and a system that is 10 years or older, it is probably a good time to replace.  You can expect the repair and recharge to cost many hundreds of dollars and putting that money towards a new system is usually the better investment.