A lot of problems may arise in your air conditioner unit over time. It is an electronic device that is held together by multiple components and any damage or fault with any one of them will affect the overall performance of the AC.
One such problem is a hissing sound coming out from the unit whenever you turn it on. An AC hissing sound may be caused due to a number of reasons, the most common of them being a leaking refrigerant gas but there are some reasons worth noting as well. Let us have a look at all of them.
5 Causes of Hissing Sound from the AC and How to Fix it
An air conditioner is a complex machine. There are many things that could go wrong with it.
Below listed are the most commonly seen easily detectable reasons behind a hissing sound coming from anywhere in your AC unit.
The most common culprit behind the AC making a hissing noise is a leaking refrigerant.
This happens because the refrigerant gas is stored under high pressure inside the copper coil and even a tiny leak on the coil will make the gas from the inside move towards this exit and all of the contents inside the coil will try and escape from that tiny crack making a resounding hissing sound.
The hissing sound is from a refrigerant leak if the AC is also emitting warm air and/or there is ice or water near the vents.
Solution: There are three things that can be done to remedy this situation but none of them are DIY.
You will need to call relevant professionals to do it.
- You can add more refrigerant instead of repairing the leak although this is a temporary solution and will cost you less than a full repair.
- Another way to deal with it is to seal the leak with some sealant and yet again this will only hold for some time and may even worsen the damage.
- The only proper solution to this problem is to get the coil replaced entirely. This will be a permanent solution although the costliest one.
High Pressure inside the Compressor
The compressor or the condenser is located in the outdoor unit of an Air conditioner set-up. If you find a hissing sound coming from the ac outdoor unit then the situation may be quite critical.
This hissing noise may sometimes be accompanied by bubbling noises and also a shrill sound at times. This means that there is a pressure build-up inside the compressor and it is not able to handle this amount of exertion.
Solution: If you hear such a sound then immediately turn off the air conditioner and call for an AC technician as soon as possible because hissing sounds from the compressor are not a good sign and this could mean extensive repairs which will cost you a lot.
The repairs will be based on the type and grade of the compressor, as a two-stage can only be replaced by a two-stage compressor, you cannot opt to upgrade or downgrade your compressor unit.
Usually, the compressor hissing and bubbling indicates that the problem may be beyond any repair and in such a case it is best to get the unit replaced. It will cost you some money but this will ensure that the compressor runs without any complications in the future.
The Air ducts are Leaking
Another probable reason behind a hissing air conditioner is probably because the air ducts have developed a leak and the sound you hear is the air escaping through the tiny leak causing a shrill and high-pitched hiss in the process.
If you suddenly notice that the air intensity coming out of the vents has lowered and the room is not easily getting cold, even after setting a low temperature on the remote and the highest fan setting, then it is worth checking the ducts because there is probably leak and the air is escaping before it reaches its destination.
Solution: Try to hear and determine where exactly the hissing is coming from and if that apportion of the duct is located in an accessible area then try to seal the leak with some strong sealing tape.
If however, you fail to locate the source of the leak then call a technician to deal with the issue for you.
Line Sets damaged by debris
A line set is a semi-flexible copper pipe, a couple of which are installed in every AC and connect the outdoor heat pump to the indoor evaporator coil.
These carry moisture and liquid to and fro between the two units of an AC unit and the part of the line set that is located outside the living area can easily get damaged by falling debris such as branches, and stones or can even get physically impacted by something thrown at it.
If a crack appears on the copper line set it will start to leak the air it is carrying and make a hissing noise.
Solution: The way out of this is to build a barrier around the outdoor unit of the AC. You can either build a shade that is suspended above the outdoor unit or build a brick fence around it and also place the AC somewhere elevated so that it does not sit directly on the outside ground.
Broken reversing valve in case of a Heat Pump
This is relevant only if you have a heat pump that both cools and heats instead of only the cooling function an AC performs. If the heat pump of the ac is making a hissing noise it could be because of the reversing valve whose role is to control and switch the flow of the refrigerant gas to perform both the heating and cooling functions.
A broken reverse valve is hissed because it is stuck between the heating and cooling settings and can perform either properly. That is to say, the heat pump will either cool or heat your house well with a faulty reverse valve.
Solution: A broken reverse valve is often an indicator of some other underlying problem with the unit and therefore it is best to get the opinion of a relevant professional so that they can fix both the valve issue as well as any underlying issue if they exist.
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Over time it is natural for an air conditioner to develop certain problems. The trick is to take care of the AC so that it will take care of you and you can do that through regular maintenance.
An AC must be maintained by a professional at least twice a year if it is used extensively and once a year with sparse usage. In that way, you will be able to get a head-on with problems such as these and fix them quickly before it develops and increases.