I have a three ton unit and when the AC guy came out and did a reading on my unit with a Yellow Jacket Manifold and it said something like 65 on the blue and 305 on the red gauge. I don't know what it means, but you probably can talk to a pro at home depot to find out more. Btw, I am by no means a professional and the only reason I wanted to know is so if they have to come out again and they check it, I can show them the previous reading, and they will know if it has a leak.
One more thing. Another interesting step the AC man did was check the temperature of the air at the intake vent and at a regular vent that blows out air. The easiest way you can do this is by getting a cooking thermometer for a couple of dollars that goes to like 40 degrees and goes up to 100+ degrees. If the temperature is 20 degree drop from intake vent to blowing vent, your AC is working as it is intended. So before you call the AC man like I did, it is a good little test to do and it is better than paying the AC man $300 to tell you nothing is wrong.
Another Opinion...
A homeowner is not equipped to check the refrigerant levels in a residential unit. It is illegal and dangerous if you don't know what you are doing. Refrigerant is under pressure and if you are not careful, you can burn yourself to the point of frost bite in less than a couple of seconds and it could blow in your eyes causing instant blindness.
Secondly, the pressures are not constant. They vary based on the ambient temperature. It takes a skilled tech to know how to properly assess the refrigerant level and determine if a machine is working properly. As a home owner, the best thing that you can do before calling on an expensive technician is to make sure your air filter is clean...restricted air flow will actually freeze up your system! The second thing is to be sure that your coils are clean on the condenser (outside unit.) If you are ambitious, you may be able to check the inside coils and blower blades to be sure they are clean. (BE SURE THE POWER SUPPLY IS OFF.) Finally, check the obvious...batteries in the thermostat and power to your system- did a breaker pop...if so, there may be a reason and this may be enough of a reason to call on your local technician.
As for temperature drop, a good system should be able to cool the air about 20 degrees F. Measure this at the return going back to the air handler and again at a supply duct.
It a word, no. Without a leak, the freon level in your unit should stay the same for years and years.
Either the t stat is way out of calibration or it is not level.
You can find a Freon leak in a home Ac unit by using a leak detector. These instruments are capable of detecting trace amounts of Freon and pinpoint leaks.
16
The refrigerant (freon) in any air conditioner should last the life of the unit. If not, you have a leak.
4 pounds
Never. A properly operating AC unit will have no leaks, thus never need recharging.
Yes you can if you have the tool, knowledge, and of course the freon. Youtube has instructional videos to help you.
$100
No, it should not leak freon because it is supposed to be a sealed unit.
Depends on the size of the unit and when it was built. Modern A/C units contain no Freon (R12). It was banned in 1996. Call a home A/C professional.
Adding freon to an air conditioning unit should only be done by a certified technician. It is in fact illegal for anyone to add freon to air conditioning that isn't properly certified, so one would add freon by calling in a certified technician to do it for them.