Modern technology is so sophisticated that one does not even realize its everyday presence. Look at the air conditioners of today; they operate silently and tirelessly to maintain a comfortable temperature in your home.
Everything is hunky dory unless they start acting weird or making noises. Any noise in an otherwise calm home can be distracting and disturbing to your peaceful life.
The most common noise that an air conditioner makes is the hissing sound. So, what is this hissing sound from AC and how to fix it? Well, tax yourself no more as this post will cover all that you need to know about the problem.
What Does Hissing Sound Like
When you let out air from a small opening, the sound that is produced is the hissing sound. As a child, you must have noticed how a leaky cycle valve made a sound as air was let out of it. It came out in a hiss. This is the sound that you are most likely to hear from your air conditioner.
Are All Hissing Sounds An Indicator Of A Problem
All hissing sounds coming from the AC do not indicate an issue. If the sound goes away in a few seconds, it is nothing to be worried about. On the other hand, if the sound is continuous, you need to be on the lookout for a potential problem.
What Is The Hissing Sound From AC
The hissing sound from AC could indicate to a couple of things that may need to be fixed.
1. Leak In Refrigerant Line – A gas leak or a refrigerant leak mostly occurs in air conditioners which are old and those in which maintenance has not been given priority. In old air conditioners, the coils which contain the refrigerant corrode over a period of time and develop cracks. Under high pressure, the gaseous refrigerant escapes from these cracks with a hissing sound. In the case of ACs seasonal maintenance has been overlooked, the refrigerant coils may freeze and in extreme cases even burst. This causes the refrigerant to come out with a hissing sound.
2. Leaky Internal Valve – There is a valve in the compressor which controls the pressure of the refrigerant. Often this valve develops a fault and starts to leak. When this internal compressor valve starts to leak, it produces a hissing sound.
3. High Pressure In Compressor – The AC compressor may malfunction due to very high pressure inside it. This can produce hissing, shrieking, or groaning sounds. If you hear any of these sounds immediately shut down the AC and call your local HVAC technician without wasting any time. Since the compressor is the most expensive component of your AC, it would be foolhardy to let this matter slide.
How To Fix The Hissing Sound From AC
Once you know where the problem lies, fixing the hissing sound coming from AC is not too complicated. Yes, it may be something that you cannot do on your own, but remember your AC is a piece of expensive machinery which is best left to the experts.
1. Fixing Leaking Coils – Ideally, only a trained technician should handle this job primarily because they can effectively detect all sources of leak and close them properly. Also, only they can tell you whether the leaks are worth fixing or you need to replace the coils. Besides, when a trained technician fixes the refrigerant leak, he will also test its effectiveness, and only once he is satisfied will he top up the refrigerant to the prescribed level. These are certain things which you may not be equipped to handle.
2. Fixing Faulty Compressor Valve – The only way to fix this problem is by replacing the faulty valve with a new one. Again, as this is something for which you will have to open up the compressor unit, it is best handled by trained personnel.
3. Fixing High Pressure In Compressor – In order to fix the high-pressure problem, it is necessary to understand its root cause. This is one thing which only a trained HVAC technician can identify. So your only option is to switch off the AC and call your HVAC company for help. While the problem persists, do not use your AC as it could kill your compressor completely.
When Is Hissing Sound Not A Problem
As mentioned in the very beginning, all hissing sounds need not be alarming. Sometimes it may be a normal sound which your AC produces in the course of its operation. If that is the case, the hissing sound will be short and small. It is very normal for the expansion valve to make this kind of noise. When the refrigerant gas present in the valve expands, it makes the hissing sound. Nothing to worry about here.
Sometimes the ductwork may also produce the hissing sound, but this will only happen at the start of a new cycle. If you find this sound irritating, just open up your air registers a little more. However, if the hissing sound is constant and high, you have to look for its cause. In some cases, the hissing sound may turn into a screeching or whining sound as well. Now you need to be worried and get your AC technician pronto.
Our Final Thoughts
Any sound which your AC was not making in the beginning but has now started to produce needs to be checked out. There is always a reason why suddenly your AC is making strange noises. If it is an unknown sound, it could indicate a problem brewing in the AC.
The best course of action is to book an appointment for your local HVAC expert to come and check out things for you. The bottom line is that you do not ignore any abnormal sounds from your AC. Ignoring the problem will not make it go away; it will only compound the issue resulting in high repair costs. In the worst case scenario, it may kill your AC entirely.
Frequently Asked Questions – FAQs
There are 3 possible reasons why your AC is making a hissing sound. These are:
1. Leak in the refrigerant line.
2. A leaky internal valve.
3. High pressure in the compressor.
In all the 3 cases, no homeowner can do anything. Their best is to call the HVAC technician as all the corrective measures involved will require specialized skill and knowledge.
If the hissing coming from your AC is long drawn out or continuous and loud enough to be distracting, it is a sign of a problem. You might be dealing with a leak in the refrigerant line, a leaky or faulty internal valve, or pressure problems in the compressor. One can only identify the precise nature of the problem after a thorough inspection of the unit by a professional technician.
A hissing sound is not always a sign of something being wrong. If the hissing is short and small, it is a normal sound the expansion valve makes when the AC runs. Even the ductwork may sometimes produce a hissing sound. The key is to remember both these sounds are not continuous or jarring enough to be distracting.
Whistling sounds from the AC indicates airflow problems. To stop your air conditioner from whistling:
1. Replace the dirty air filter with a clean one.
2. Ensure the vents and registers are not closed or blocked by furniture or appliances.
3. Open the dampers.
4. Too many doors in the home might be closed. Opening them will also help eliminate the whistling sound.
The refrigerant or the coolant in the AC is continually under pressure while the unit is running. When the AC is switched off, the refrigerant depressurizes, and this is what produces the hissing sound. As soon as it has depressurized, the hissing sound stops.