300 posts, read 688,560 times 284 posts, read 1,119,417 times 3,702 posts, read 13,835,465 times 14,718 posts, read 15,190,421 times 13,664 posts, read 13,229,960 times Originally Posted by NeilVA I'd have to disagree with that assessment as a low charge would likely result in long run times. Compressor cycling on 3 times an hour (and staying off 50% of the time) in 100 degree temps seems to indicate the unit is functioning normally. If you have a meat thermometer, stick it in through one of the canvas transitions just in front and just after your indoor blower section. You should see about 20 degrees difference between the two readings. 1,963 posts, read 3,537,811 timesHow Long Should an Air Conditioner Cycle Last? During hot weather your air conditioner runs a cooling cycle that chills the evaporator coil using rapidly expanding refrigerant. Fans draw air over the coil and force the air through the ducts that lead to the rooms in your house to lower the overall temperature.

This cooling cycle runs for a few minutes until the temperature is right; central air conditioning unit not producing cold airit then shuts down to save energy and prevent the air from getting too cold inside. what does it mean when your ac unit has ice on itHow long the unit runs a cooling cycle varies based on several factors.green hvac units Your air conditioner’s cooling cycle should last until it cools the house to your preference. There is no set time it should run. Instead, the cooling cycle is designed to create colder air in the house until the temperature on the thermostat is reached. It shuts off at that point and starts again when the house begins to warm up naturally. If it is just slightly warm outside, it probably won’t run more than a few minutes.

If it is blazing hot when your temperature is set fairly low, it may need to run much longer to reach the goal temperature. How long your air conditioner cycle lasts may also be affected by the size of your system. The size of an air conditioner is measured in output BTUs. This indicates the amount of cooling it can produce in a given time. One BTU is equal to the amount of energy needed to raise the temperature of one pound of water by one degree Fahrenheit. If your air conditioner has more BTUs than it needs, it will run very short cycles more often. If it has too few BTUs, it will run much longer per cycle. Assuming your installer recommended the perfectly sized central air unit for your home, it should be able to get both of its jobs done in seven-minute to 10-minute cycles. The air conditioner does more than blow cold air. It also removes moisture from the air to make the home more comfortable. If properly sized, the air conditioner will cool to the desired temperature and remove the proper amount of moisture within this time frame.

The Long and Short of It If your air conditioner tends to run cycles much shorter than seven minutes or much longer than 10 minutes, there is a problem. Short cycling will overwork your air conditioner and use up unnecessary energy from starting and stopping cooling. It will also leave too much moisture in the air. Longer cycles have the obvious downfall in that they use excessive power to run the cycle for long periods of time. Chas Roberts Air Conditioning and Heating: FAQs SRP: Air Conditioning and Heat Pumps How to Calculate Air Conditioner Size for a House How to Buy Air Conditioners Refrigerator Freezer Fan Will Not Shut Off How to Stop a Window A/C Unit from Leaking Inside the House How to Convert Evaporative Cooling System to Central AirThe requested URL /showthread.php?t=7864 was not found on this server.Image 1 of 5 My big fat oversized air conditioner. I did a little doctoring of this photo, but using a data logger showed that the air conditioner I had installed in 2009 is definitely oversized.

Back in 2009, I had a new air conditioner installed our condo. It wasn't cooling much, and the summer electric bills had risen. So, I did a Manual J load calculation on our condo to find out what size we should replace it with. There's this thing called the summer design temperature, which is the temperature that your location goes above only 1% of the time. As I wrote in an earlier article about how to find out if your AC is oversized, I wanted to go with the 1.5-ton AC, but I chickened out and put in a 2-ton unit instead. Our place is about 1,500 square feet, so that's 750 square feet per ton. That day was last Friday August 29, and I looked at the 24-hour period from midnight to midnight.The thermostat was at 75°F for nearly the whole day. The only time it wasn't was in the early morning morning when I lowered it to 74°F. Our design temperature in Atlanta is 92°F. Last Friday, we had a good 5 hours when the temperature stayed right there, around 91-92°F. We had another couple of hours above 89°F, so it was perfect for seeing if our AC is oversized.

From 6 p.m. to 7 p.m., the AC was on for 31 minutes and off for 29. Note that the first graph isn't showing the actual on/off cycles. Over the whole 24-hour period, the air conditioner went through 35 cycles, as shown in the second graph. A: Contrary to popular belief there, is no rule of thumb for sizing a system to a home. The only way to insure the size of the system you purchase will be large enough to cool your home, but not any larger than you need, is to have your home’s individual heating and cooling needs evaluated by a licensed professional. I have an air conditioner that is probably 15 years old now. The problem is when I turn it on after it has been off for a long period of time (several hours) it takes a long time for the outdoor unit (compressor?) to start running. The outdoor unit has a large fan in the middle with cooling coils around the perimeter and cooling fins. It had been running just fine up until three summers ago. Two winters ago, my heater went out and I had it replaced.

The following summer (last summer) I went to turn on the air conditioner for the first time and it took so long (30 minutes) to come on that I thought it was broken or not wired up or a fuse blew. I checked all the obvious things like the set temp was below the room temp. The wall unit has a red light that glows when either the heater or air conditioner unit is operating. I figured the heating & cooling guys forgot to hook something up. Having a bit of electrical know-how, I went and checked the outside fuses and other things and could see the outdoor unit had voltage going to the outdoor unit. Just today, first time turning on the air conditioner for the year and same behavior. Here is the interesting thing though. Once the unit kicks on, it cycles normally. I can hear a small click (relay closing) on the inside thermostat unit each time the termostat cycles on/off. I can then hear the outside unit kick on within a few seconds of hearing that click (normal). On mild days, I turn the air conditioner off and it may be off for a day or two but then turning it on for the first time, I can hear the thermostat click but the outdoor unit takes 30 minutes on average to come on for the first time.

I don't have a schematic for the unit but I can't imagine an outdoor relay taking that long to engage if it's a relay problem. Also the outdoor unit has this blanket around the motor. I tried removing it when this problem first began but the unit seems sealed up. The guys that put in my new furnace insist they did nothing that would have caused this but want $85 to come look at it. Anyone recognize this behavior? There is probably an old capacitor in the electronics which dried out over the time and now takes a long time to gain the necessary power load. If you are familiar with electronics you can check yourself for capacitors which looks bloated or otherwise funny and replace them. I know that when a capacitor fails to start up it can cause the compressor to overheat and it will simply be slow to start. Therefore switch off the power, and after it gets cool, replace your capacitor for proper operation. And if you are in a hurry, you could pour some fresh water to the compressor to cool it.