It is important to pay attention to the noises you hear coming from the air conditioning system. Those noises are not just random; they are telling you something about your HVAC system. That is why you need to make pay attention to the noises your HVAC system makes.
Cause #1: Refrigerant Leak
The first thing you need to check is the refrigerant. The refrigerant is the blood of your HVAC system; it helps keep everything running and ensures that your HVAC system is able to stay at the right temperature and produce cool air when you need it.
When there is a leak in the refrigerant line or the system, you may hear a hissing sound. That may not be the only thing that you notice. You may also see liquids dripping from the air conditioner lines or you may see liquid pooling around the air conditioning system. The liquid around the HVAC system is not a good sign; you need to turn off your HVAC system and find the source of the leak.
Cause #2: Valve Leak
Another reason that your AC system may be hissing is that a valve is leaking. A leaking valve is not a huge issue; but it will make a big, annoying sound. Finding the right valve that is leaking can take some time though.
If you want the leaking valve fixed in a timely manner, you'll want an AC specialist to come out and find the damaged valve. The damage valve will need to be replaced as soon as possible. When damaged valves are not replaced in a timely manner, the result may be a refrigerant leak.
Cause #3: Compressor Issue
The other reason that your air conditioning unit may be making a hissing sound is that there is something wrong with the compressor. A hissing sound is produced by the compressor when the pressure inside of it is too high.
This is a really serious issue. If you suspect that the hissing sound may be coming from the compressor, you need to turn your AC system off and call in an expert right away. You don't want the compressor system to explore. A hissing compressor will generally be louder than the hissing sound created by a refrigerant leak or a valve leak, and the sound may continue even once you turn off the unit as the pressure has already built-up inside.
When your air conditioning system starts to make a hissing noise, you need to call an AC repair professional in order to fix your system right away before the system sustains any more damage.