20,317 posts, read 15,073,405 times 25,901 posts, read 21,074,479 times 33,571 posts, read 32,296,961 times When a central air conditioner freezes up, what actually freezes is the condensor unit's evaporator coil. This is the part of the air conditioning system that transfers (evaporates) heat from the inside to the outside of the home. There are two primary reasons the evaporator coil may freeze, it can either be due to 1) restricted air flow, or 2) lack of sufficient refrigerant. Either way, the result is that the air conditioner's evaporator coil cannot operate to properly dissipate heat, and in effect 'overcools' itself. The result of this super-cooling is condensation (that's water formation), and eventually ice from that condensation as it cools below the freezing point. Yep, the A/C just turned into an old-school icebox. Basic Tips for AC Repair and Maintenance Filter is brand new. he checked air flow and temp conversion etc. The unit is 12 years old and never used hard.

I never have my temp below 76 in the summer. Input and out put lines also freeze so does the tank inside the unit out side. Its a carrier high eff. Originally Posted by AksarbeN What ever he did seems to have made it worse. 2,322 posts, read 2,396,739 times Originally Posted by tinman01 Well contact him to return and 1. either fix it properly or 2. you will have someone else do it and he will eat cost of the service if it is determined that his initial work, indeed made things worse. 222 posts, read 301,003 times inexpensive fiberglass filtershigh dollar thick filters restrict too much air flow I noticed my house wasn't getting under 75°F this weekend when I had the thermostat set for 70°F. Since I'd done a lot of drywall sanding inside recently, my first idea was to replace the filthy air filter. My first indication that the air filter wasn't the root cause was when the return didn't have enough suction to hold the air filter in place while I was replacing it.

I went outside to look at the compressor unit and discovered the exposed portion of the refrigerant line running into the house was frozen, but the fan was still running. The evaporator drain line still had a steady stream of water coming out of it. After turning everything off and waiting for the line to thaw, I turned the thermostat back on. Cooler air came out of the vents, but it didn't seem to be blowing with much force, and it wasn't as cool as it should be.can you turn a window ac unit on its side I went back outside and discovered the refrigerant line was already frosting up again. how much does a ac unit fan costAt this point it was already dark, so I turned everything back off and slept with the ceiling fan on. mini split unit wiring

Other random notes that may or may not play a factor: The AC unit had been sitting idle the past 3 days since we had nice weather in the mid-70's last week. I mowed the lawn next to the condenser unit the day I noticed it stopped working. However, I was bagging the grass clippings, so nothing should have been blown into the unit. Any ideas on the root cause of the icing and lower air flow? I wouldn't think the two would be connected normally. Is it something as simple as low refrigerant levels? I plan on going to look more closely at it after work today. What are some other things I should pay attention to? UPDATE: I checked the system after work today and decided to give it one more chance after I couldn't find anything wrong with it. After a few hours, it had brought the inside temperature down from 80°F to 75°F. I periodically checked the refrigerant line for freezing, but it never got much colder than 60ish degrees. I think the root cause was the air filter, and that I didn't allow enough time for the line to thaw last night.

UPDATE 2: Maybe I drew conclusions too soon - I just checked the refrigerant line and discovered frost on it again. The inside temperature was at 72°F while the outside was at 66°F. I think pumping warm air to a cooler outside temperature may have contributed to the icing, but I'm not completely sure. (And if you think I'm crazy for running the AC when I could just open the window, you'd think twice too if you saw how many bugs swarm my porch light and windows every night. Dozens of them somehow find their way past the screens if I open the windows.) I plan on running it again tomorrow during the day and monitoring the refrigerant line temperature every few hours. If it freezes up again, I think I'm going to cave and call a repair guy. UPDATE 3: I totally forgot to follow up on this. It froze again, so I called an HVAC repair guy. He checked the system, added refrigerant, and problem solved. I think the bill came out somewhere around $150 for the service call fee and refrigerant costs.

You may be looking at the problem backwards, the freezing lines could be a symptom of the problem not the cause. Start by looking for blockages in the system that would cause lower air flow / heat exchange. Basically if the system cannot exchange the heat/cold, it will not function properly and could lead to over heating/cooling. Frozen lines could also be caused by high or low levels of refrigerant, so you'll want to get a service person out to check the refrigerant levels. Here is a really good image to visualize how it works. My A/C's frozen up before due to insufficient airflow over the evaporator coil. Turns out those $20 allergen-blocking air filters can slow down the air too much, so I switched to a cheaper one that doesn't block the air flow as much. My A/C guy also told me that running the A/C when it's cooler outside than inside can cause it to freeze up in certain conditions like low airflow or low freon. My guess is a dirty "A" coil or blower wheel.