AC can't keep up with the thermostat setting when it reaches extreme temps
#1
09-03-17, 10:54 AM
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AC can't keep up with the thermostat setting when it reaches extreme temps
Our ac works great until it becomes 100+ degrees outside then it just pushes out somewhat cool air. Our thermostat is set to 74 degrees and when it becomes super hot outside it says the house is at about 82 degrees. What would you recommend we do to make our ac blow cold air again? Just clean it out? Maybe recharge it or something like that? Our unit is a bryant on roof system
#3
09-03-17, 08:40 PM
First question is did it work correctly before? Did anything change? How are your electric bills compared to last year?
It is normally recommended that a system have a maintenance check every year. Was that done? There is not a lot you can do other than replace the filters and check in the attic for air leaks.
It is normally recommended that a system have a maintenance check every year. Was that done? There is not a lot you can do other than replace the filters and check in the attic for air leaks.
#5
09-05-17, 10:15 AM
Of course, we tend to notice that we're not getting as much cooling as we want when the outside temperature is hot as blazes.
I just came home from a trip during a record breaking heat wave, and it seemed to take forever for our a/c system to cool the house, which had gotten very warm. I think part of the problem was that everything in the house had gotten very warm, so the cooled air was being re-warmed by everything it touched.
So, yes, closert's question is central -- how much cooling is the a/c unit doing to the air? In discussions, I usually see something like 20°f (difference between intake and vents) is not bad. So, if your house is at 90° and the system cools the air to 70°, it's working fine but it is going to be a while before the house feels comfortable. But, even that 20°might be overly optimistic, even if the system is working well, if you have a lot of humidity. It was explained to me that a/c systems mostly dehydrate humid air before they really get much cooling going.
If you haven't changed the filter recently (most people haven't), it might be reducing airflow so the cool can't be efficiently picked up from the coils. So, that's something to check out and easy to deal with yourself.
Air cooling generally starts with compressing the coolant then blowing outside air over it (in coils). Of course, if it's really hot and dry outside, then that's unavoidably less efficient.* However, one time we noticed our a/c not performing well so called out a service-person who discovered that the coils themselves were coated with dust which acts as unwanted insulation, reducing the cooling effect. What I really appreciated was that he showed me the 'massively high-tech' way he dealt with this problem -- get a garden hose with a narrow, pressure nozzle, and squirt it extensively and vigorously through those vent holes in the side of most a/c outdoor units (you know the box that makes that noisy fan sound). I was amazed at how much of a difference that made, instantly. Since your a/c unit is on the roof, that might be another reason to let a professional do the work.
Recently, our a/c stopped cooling, so we called out a serviceperson. He reported that the system was broken and had be replaced, for lots of $$. I paid for a 2nd serviceperson inspection; he reported that the coolant was gone, apparently due to a loose connection, so he tightened the connections and re-charged the system (for much less than the cost of a replacement). He said, maybe there's a leak we can't find and stop, so if it discharges again we'd need to replace the system. That was 2 years ago, and the unit is working just fine.
*I suppose recommending that you will be much happier using your a/c when the weather is cool and damp -- would not really be helpful.
I just came home from a trip during a record breaking heat wave, and it seemed to take forever for our a/c system to cool the house, which had gotten very warm. I think part of the problem was that everything in the house had gotten very warm, so the cooled air was being re-warmed by everything it touched.
So, yes, closert's question is central -- how much cooling is the a/c unit doing to the air? In discussions, I usually see something like 20°f (difference between intake and vents) is not bad. So, if your house is at 90° and the system cools the air to 70°, it's working fine but it is going to be a while before the house feels comfortable. But, even that 20°might be overly optimistic, even if the system is working well, if you have a lot of humidity. It was explained to me that a/c systems mostly dehydrate humid air before they really get much cooling going.
If you haven't changed the filter recently (most people haven't), it might be reducing airflow so the cool can't be efficiently picked up from the coils. So, that's something to check out and easy to deal with yourself.
Air cooling generally starts with compressing the coolant then blowing outside air over it (in coils). Of course, if it's really hot and dry outside, then that's unavoidably less efficient.* However, one time we noticed our a/c not performing well so called out a service-person who discovered that the coils themselves were coated with dust which acts as unwanted insulation, reducing the cooling effect. What I really appreciated was that he showed me the 'massively high-tech' way he dealt with this problem -- get a garden hose with a narrow, pressure nozzle, and squirt it extensively and vigorously through those vent holes in the side of most a/c outdoor units (you know the box that makes that noisy fan sound). I was amazed at how much of a difference that made, instantly. Since your a/c unit is on the roof, that might be another reason to let a professional do the work.
Recently, our a/c stopped cooling, so we called out a serviceperson. He reported that the system was broken and had be replaced, for lots of $$. I paid for a 2nd serviceperson inspection; he reported that the coolant was gone, apparently due to a loose connection, so he tightened the connections and re-charged the system (for much less than the cost of a replacement). He said, maybe there's a leak we can't find and stop, so if it discharges again we'd need to replace the system. That was 2 years ago, and the unit is working just fine.
*I suppose recommending that you will be much happier using your a/c when the weather is cool and damp -- would not really be helpful.
#6
09-06-17, 08:27 AM
Member
There is no set max temperature difference between inside and outside.
It depends on how it's sized.
In a hotter climate, you'll have a larger unit.
If it's running continuously and rising up to 82f, there's a problem for sure - many things can reduce capacity.
If you're raising the setting and expecting it to cool back down when it's 100f, stop doing that, it's a big part of the problem.
By all means shut it down or raise the temp if you're away from the house for 24 hours or more. but when you're away for work or something, in really hot weather set it to a moderate temp like 75 to 78 and leave it alone.
It depends on how it's sized.
In a hotter climate, you'll have a larger unit.
If it's running continuously and rising up to 82f, there's a problem for sure - many things can reduce capacity.
If you're raising the setting and expecting it to cool back down when it's 100f, stop doing that, it's a big part of the problem.
By all means shut it down or raise the temp if you're away from the house for 24 hours or more. but when you're away for work or something, in really hot weather set it to a moderate temp like 75 to 78 and leave it alone.
#7
09-06-17, 08:47 AM
Originally Posted by JJackson821
Our unit is a bryant on roof system
So, if you've got an on roof system with no shade on a dark roof in Arizona or New Mexico, then it's no surprise that it's not cooling effectively.
Think of thermal inertia. Old adobe houses cooled down in the evening, stayed cool through the day. Paradoxically, your best bet is to cool the house down at night, when it's cooler, which is easier on the AC unit. If you're waiting UNTIL it's hot, and then trying to cool it during the hottest part of the day, that's not going to work well.
#8
09-06-17, 10:01 AM
Member
So, if you've got an on roof system with no shade on a dark roof in Arizona or New Mexico, then it's no surprise that it's not cooling effectively.
Sun shining on the coil has little impact. It's air temperature.
And when they size the unit, they're supposed to de-rate it for the heat. They're rated at 95f and lose a little capacity at is gets hotter.
If it regularly hits 100, it should keep up at that if sized, setup, and installed correctly.
Something is wrong. It will take a skilled technician to figure out - skilled being the key board.
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ignore stupid user name, trying to get it changed.
