For a good charge, the low-pressure gauge should read between 25 and 40 psi (pounds per square inch), and the high pressure gauge should read between 225 and 250 psi. Another useful tool is a refrigerant scale. A scale will allows you to know how much refrigerant (by weight) was actually added.
You can test this by adding a few ounces of A/C Pro®, as explained in the can's instructions. If the compressor then starts running, you know that the problem was low refrigerant, and you can finish adding A/C Pro® until your A/C is running cold again.
After keeping the AC on for 15 minutes, check the outdoor of AC if it is heating or not. If hot air is coming out of the outdoor of AC, then the gas pressure is okay. You should then check the pipe of the AC if it is hot or cool. If the pipe is cool, the AC is working well.
Having too much refrigerant in your AC can damage the compressor. This can happen because the excess refrigerant will likely collect inside the compressor and cause subcooling, wherein temperatures are below normal. Furthermore, the extra refrigerant can flood the compressor and damage its mechanical parts.
Shake the can or strike it with your fingernail. If it feels like it's empty, it is.
An AC leak will lead to warmer air from your vents over time. In most cases this can be fixed with a proven stop leak additive to seal up any leaks. When it's time for an AC recharge, turn to AutoZone.
At an ambient temperature of around 75°F (24°C), the low-side pressure typically ranges from 35 to 40 psi. As the ambient temperature increases, the low-side pressure may rise slightly. For example, at 85°F (29°C), the low-side pressure might be around 45 to 50 psi.
Refrigerant is a working chemical that runs through your car's A/C system in either a gaseous or liquid form. Causes of refrigerant leaks in your vehicle include physical damage, wear and tear over time, and escaping refrigerant even without a leak.
First, check your filters and coils for dirt and debris that may be impeding airflow. Once you've cleaned the filters and coils, run the air conditioner with just the fan so that the ice accumulation can melt off. If the AC still doesn't blow cold air, it could be that refrigerant levels are too low.
Too little refrigerant also risks freezing the evaporator coil inside your home. The first problem with a frozen coil is the airflow restriction it causes, preventing air from circulating back out. The second problem is the water it creates once the ice melts, risking further damage around your AC.
Like your engine oil dipstick, your air conditioning system does not have a set level. There is a range of low-side and high-side pressures that are acceptable and vary depending on the ambient temperature. However, generally your low-side pressure should be 30 to 40 PSI and high-side pressure should be 150 to 175 PSI.
One of the most obvious signs that your vehicle needs a Freon recharge is that your vehicle will be blowing warm air, even after your vehicle has been running for some time. If your refrigerant gets too low, there will simply not be enough “coolant” to cool the air as it is passed through your evaporator coil.
All new compressors from Classic Auto Air contain a full system charge of oil. Do not use more than 24 oz. of 134A refrigerant! 1.5 lbs. or 24 oz of R134A is what is required.
The short answer is that the Global Warming Potential (GWP) of HFC-134a is significant and there are replacement gases available that have less environmental impact. The EU has banned most uses of HFC-134a.
It is important to be aware and recognize the warning signs of low refrigerant to avoid further damage and costly repairs. If you notice weak airflow, inadequate cooling performance, warm air from vents, constant short-cycling, ice buildup, or unusual noises, take action.