subject: My Air Conditioner Does Not Cool My House [print this page] My Air Conditioner Does Not Cool My House
If your air conditioning systems seems like it does not cool your home, this article may help you access the problem. If your air conditioner is broken and won't turn on, this article is not going to help and you'll have to read on of my other articles on the subject of air conditioning repairs.
First things first.
ARE THE COILS CLEAN?
We will assume that your air conditioner was sized properly for your home, that it was properly selected based on the area you live in, the average mean temperature of your area, the average humidity in your area and the rest of the calculations used to determine the proper heat load of your home. If your system was undersized, there may not be much you can do about it, but if it was correctly sized and now seems as though it won't cool we can proceed.
The first thing you have to be absolutely sure of is that the indoor and out door coils are clean. Make sure that the condenser coil is clean, turn off the power and physically look at the coils, if theres any dirt at all on the coil, you can either wash them off your self or you can have them cleaned by a professional. I'm not going to tell you how to wash the coils in this article, only that its important that they are clean. If the out door coils are dirty, then the air conditioner can't get rid of the heat it picks up from inside the house.
The evaporator coil must be clean also, this coil is much trickier to clean than the out door coil, and it really should be done by a professional. A good indication if the evaporator coil is dirty, is to look at the blower wheel, and blower motor inside the furnace, if you see dust caked all over the motor, chances are that the evaporator coil is dirty. You must be sure both the indoor and the out door coils are clean.
IS THE FILTER DIRTY?
Don't even guess about the air filter, take it out and change it. I don't want it even a little dirty.
Does the air conditioner stay running, or does it shut down.
If your room temperature is 80 degrees and you set your thermostat to 74 degrees, the air conditioner should come on and stay running until it meets temperature. If the outside unit, or the indoor fan shut down at all before the system meets temperature, then you have a problem that needs immediate attention. So make sure the unit continues to run the entire time its in a call for cool.
DOES THE OUT DOOR FAN STOP RUNNING?
If you put the t-stat in a call for cool, and the out door unit starts running, its important to make sure that the out door fan continues to run the whole time, while the compressor is running. If the fan stops running and the compressor runs by it self, your going to have major issues. If someone did a repair to your air conditioner due to a failed fan motor, with out testing to ensure the compressor valves are still good, the compressor may have been damaged by over heating and over pressure, you would need a professional to diagnose this.
If some one did do a fan motor replacement on the out door unit, it's vital that they installed the correct size fan motor. Its horse power and RPM must be the same as the one called for on the name plate. Because the pitch or angle on the fan blade was specifically designed to move a set amount of air given the rated motor specifications. Turn off the power and look through the grill at the motor, if you can see the sticker on the motor, compare the ratings to the sticker on the side of the unit.
IF the motor has been replaced, you might be able to look down in between the grill and see the wiring. If its a replacement motor you may see wire nuts connecting the motor to the wiring harness on the unit. If you see zip ties or tape on the wiring on the fan motor, these would be good indicators that the motor has been replaced. If its been replaced you have to remember that the compressor may have been damaged when it ran with out the fan motor. You would need a professional to come out and test the compressor valves. If you do see the wire nuts and tape, and you do suspect that the compressor if bad its time to make a major decision as to the most effective way to use your money at this point. More about that at the end of the article.
DOES THE UNIT HAVE ENOUGH FREON?
While you as a consumer probably don't have the tools to check the freon level in your unit, you can get a good feel for the units charge, by using a thermometer. If you have a digital thermometer, you can turn the thermostat to cool, turn the temperature all the way down and let it run for about 15 minutes, after at least 15 minutes, take your thermometer and measure the air temperature going into the return air grill inside the house and then measure the temperature coming out of the supply air diffuser, basically this is measuring the air in vs the air out. I would look for at least 18-22 degrees difference. It should be 18-22 degrees cooler coming out than going in.
Next go to the out door unit while its running, measure the out side temperature within five feet of the unit. Then measure the temperature of the air that the fan is blowing out of the top of unit out side, look for a difference of between 20-30 degrees between whats going into the unit and whats coming out of the unit. If your two temperatures differences are not between these ranges, you have a problem that needs addressing, call a professional and have them assess the units charge. It may be over charged or under charged.
Next take your thermometer and measure the temperature of the copper pipe that has the black foam insulation on it. On a real hot day, the line should be pretty cold, and it may even sweat with small water droplets on it. Make sure you measure the temperature under the foam so that the thermometer is not affected by the out door temperature. Depending on the out door and indoor temperatures and humidity levels I would expect the temperatures to be somewhere in the low 40's to low 50's Fahrenheit
DOES THE FURNACE OPERATE WHILE THE AIR CONDITIONER IS ON.
It is possible that the main burners on the furnace are operating while the unit is calling for cooling. If your house was painted and they installed the thermostat wiring incorrectly, or if theres a short in the electrical wiring, the burners could be coming on in a call for cool. Make sure that there is no burner flame when the unit is calling for cooling. If there is, you need a professional to diagnose the problem! Try turning the gas shut off to the off position, while you're waiting for a technician.
DOES THE AIR CONDITIONER MAKE WATER WHEN IT RUNS
The air conditioner should be making at least a dribble of water when it runs, if theres no water coming out of the condensation drain line (the white plastic pipe that comes off the indoor coil) then you probably have a problem that needs addressing. The white drain line should go outside the home some where and drain, to the outside. Find the end of the pipe and check it for water dripping. If no waterits time to call a professional and have them check the charge.
IS THE RETURN AIR DUCT CONNECTED
Make sure that the duct work in the attic, or sub floor is connected properly and that your system is not drawing in SUPER HOT attic air in the summerTHIS WOULD MAKE YOUR AIR CONDITIONER UNDERPREFORM. We just did a repair on a system where the ductwork was broken in the attic and the unit was taking in air that was 2.5 times higher than the room temperature. It could not keep up with the heat load.
If any of the problems or conditions that I described above happen to your unit, you're going to need a service technician to come out and check out your system. Basically the only real thing you as a home owner can do, is change the filter and wash the outside coil. You can take measurements but what to do with eh results will be the issue. If you need extensive repairs to your old air conditioner that uses R-22, its time to realize that the time has come when it makes more sense to replace and upgrade to 410A and its just that simple. Any significant repairs to an older R-22 system are at best A WASTE OF YOUR HARD EARNED MONEY at this point.
