Our Central a/c unit is about one year old, I did not splurge for the high efficiency unit but was assured that I bought a large enough unit for the house.
The a/c is on constantly during this little mini heatwave we are having here in Illinois but the temperature of the house never gets down to the goal temperature. It is set at 73, it is currently 75 after the a/c has run nonstop all night.
I changed the filter a couple weeks ago and that seemed to help temporarily. I just changed the filter again now, we’ll see if that improves things. The filter is huge and costs $20 per, but I suppose changing the filter monthly is better than leaving the a/c run 24/7.
Is this natural, should I just breakdown and change the filter every few weeks or should I call a guy? Or is there something else I should be doing?
Something is definitely wrong. Either the unit is undersized or it has lost some of its Freon charge.
I’ve been told that an established system losing Freon is the sign of a leak and nothing else. A relatively new system could have been under charged in the first place, or had a leak from the beginning.
Call the installer and ask for a checkup. Also, look up the rating of your unit and use online resources to see if it’s in the ballpark for your house.
Get two permanent filters. These things are designed to be removed and washed, when one is removed for washing you put the other in.
When’s the last time you had your ducts cleaned?
ETA: is the condenser outside or inside? If inside, it might not have been properly connected to the ducts. When ours was replaced, we found that about a third of our a/c and heat was being left out in the utility closet.
Sorry, got a little confused there. I meant the blower hadn’t been properly connected to the ducts until we had the heat & AC replaced. Guys from at least three different companies had been in there and none of them actually did anything about it until the fourth replaced the whole thing.
If the condenser is inside, it might not have enough ventilation. Ours has this problem but that has to do with the way this place was built. Only so much can be done with a brick wall without violating the condo association’s rules.
Have you ever cleaned the condenser fins? Even a light coating of dust affects performance. I hose mine off twice a year to get rid of the cobwebs, dust, etc.
How warm has is been during the heat wave? One can only expect about a 18-20 degree (F) differential between outdoor temp and indoor temp, so if the ambient temps have been in the mid-to-upper 90’s you may just need to bump up the interior temp a bit so the unit can cycle. Otherwise, if the unit worked fine over the last year and you just recently noticed the issue, I would suspect a Freon leak.
It’s almost never a coolant leak. It’s almost always dirt or an electrical problem. Also, 73 is too low. Most any system will struggle to get your house that cold unless the place is extremely well insulated and nearly air tight. 75 is about right.
I called the A/C installer and he said that the air temp coming out if the vents should be about 15 degrees cooler than the setting. That’s his rule of thumb.
So, if you have the thermostat set to 72 degrees F, the air should be coming out at about 57 degrees.
No idea if this is true, however. I tested mine, and it’s about 10 degrees cooler than the thermostat.
Better call that guy and get his ass back over here.
Find the best AC company in the area, and schedule a service call. Tell them to check it for coolant and see if it needs a charge. It’s only a year old, is it still under any sort of warranty?
If it needs more coolant, pay the extra $80.00 or whatever it might be for them to put dye in the system so that if it happens again like within a year, they can do a check to see if you have a leak. Checking for the leak gets expensive.
Again, check your warranty with whoever installed it, and insist they check the coolant and see if it’s low. I highly recommend you be home and watch them as they do this and ask questions.
Other than the above, I also suggest they check your duct system for leaks. Two years ago my a/c began to run nonstop during hot days and after checking my crawl space I found several leaks in the duct system. Leaking supply ducts create negative air pressure within the dwelling because the closed system circulating fan is removing more air from the living area than it replaces because of the leaks. As Nature hates a vacuum, the pressure is stabilized by warm outside air seeping into the home. After my ducts were sealed, my a/c returned to recycling on/off during the day.
FYI and in my opinion, a thermostat setting of 72 will tend to overwork most a/c compressors on hot days/nights.
Given the choice between cleaning the fins and paying for a service call, I’d suggest trying the former first. In 40 years of working with AC techs and working on units myself, the majority of problems were caused by lack of housekeeping. That goes for refrigerators, as well. Seals can collapse, and connections can fail, but refrigerant really has no place to go in a closed loop.
When I went to visit my kids two years ago, my son was complaining about his AC not cooling things down properly and running constantly. His ‘solution’ was to turn the temp down to about 65. I went outside to look at his condenser unit, and it looked like a scene out of Arachnophobia. Cleaned it off, problem solved. I went back this past July, and he hadn’t cleaned it since I left the year before. In addition, his water heater was turned so high that there was steam coming out of the taps. :smack: There really should be a Home Ownership for Dummies book. People spend a lot of money on problems that could have been easily prevented, not to mention paying exorbitant electric bills. I understand that a lot of folks aren’t technically savvy, but there’s always the internet to fall back on.
Well, that is wrong anyway. The typical differential is 15 to 25 degrees between the RETURN air and the SUPPLY air. Measure the temperature right at the filter (return air) and the temperature coming out of the vents.
The temperature of the supply air has nothing at all to do with the thermostat setting.
Is the condenser on the sunny side of the house? Unrestricted airflow around it? How about the “A” coil, does it have a build up of dust, dirt? There is a spray to clean them off.
Our central AC did the same thing last week–it was blowing air constantly, but not cold air. We checked the filters (they were embarrassing!) and changed them, but that didn’t help. I called an AC repair guy, and he told me to go check the actual unit outside. He said to look for ice around the conduit thing coming out of the unit. I checked, and sure enough, there was ice around it (it was kind of hard to see–I wouldn’t have noticed it if I hadn’t been looking for it). He said to turn the temperature from Cool to Off and the fan from Auto to Manual, then let it sit for a couple hours, check to see if the ice was gone, and turn it back on.
I had to do that often in a trailer, and once here with the old A/C, but it was the inside part, where the refrigerant expands, that iced up. Air can no longer blow through the fins or vanes, and more ice is produced.
I think it was on the 'Dope that a HVAC guy said it indicates low refrigerant.
I didn’t know they would tell you that, I thought they came over, did it themselves and charged you a couple of hundred bucks.
One theory is that it is caused by low refrigerant.
When the A/C runs constantly, those pipes are always cold. Ice begins to form and restricts air movement, so it becomes even colder. The fan cannot move air through the fins, and warm air comes out.
If you can leave the fan set to “on”, the pipes and find warm up when the A/C is not running.
Let me ask this question then. As a home owner, what is the best way to check to see if the A/C unit is operating properly? Is there an easy way to check the temperature of the coolant, or do I average the output from each return vent and subtract that from the average of the air temp entering each supply vent?
If I have a guy come out to the house, what would he check? Would he go to the unit and measure the coolant temp, or would he measure the air temp in and out of the system?
