Why is my AC making a hissing noise?

July 25, 2019

A hissing noise coming from your HVAC system is not something to be disregarded. Among the potential causes are leaky refrigerant lines, an internal valve leak or a serious failure with your compressor. If the hissing noise is heard from your air ducts, then you could have leaking air ducts. This is annoying, but not necessarily something to panic over. A hissing sound may be a sign for any of these things, but we’ll try to narrow it down further.

Does the hissing sound end after a few seconds?

If you hear a hissing noise that stops after a few moments, you may not have any problems. That might be refrigerant in your expansion valve, which is a part of the normal operation of your HVAC system.

Is the AC Making a Hissing Sound with Bubbling Noises?

Are you hearing a bubbling sound paired with a hissing sound? This may indicate a refrigerant leak. If a refrigerant leak presents itself, you might hear a slight hissing sound as the refrigerant escapes through the leak. It escapes as a gas and can be a serious health concern. If you see signs of a refrigerant leak, shut down your HVAC and call a expert HVAC company to come take a look.

If the cause is a valve leak, it should be repaired by a qualified technician as soon as possible. The job of the valves is to manage the pressurization of the refrigerant gas and without repair, the leak will worsen. When it does, the hissing sound will often intensify, which can be a signal if you’re looking for a cause. You must maintain proper pressure in your system for it cool your home, and refrigerant leaks cause additional health and mechanical problems. You ought to get this fixed post haste if possible.

Are Hissing Noises Coming from the Compressor?

The compressor is found in the outdoor air conditioning unit, which is also known as a condenser. Listen nearby the condenser for the hissing noise. If the compressor is the cause, this could be a dangerous situation because it is a signal that the pressure inside the compressor is too high. If you hear hissing, whistling, or shrieking coming from your compressor, power down your air conditioner pronto and call a professional technician.

AC compressor located in exterior condenser unit 

Compressors are some of the most pricey parts to repair or replace inside an AC. Compressors are the part responsible for circulating refrigerant through the system. You cannot turn on an air conditioner and cool your home without a compressor. The expense varies based on factors such as the type, unit size, and brand requirements. If you have a two stage compressor in the unit today, you would need to replace it with a two stage compressor. It’s impossible to upgrade or downgrade the compressor type - your unit has specific requirements for what parts are installed and won’t accept substitutes. While it’s impossible to give a quote online because of the variable costs, the receipt is frequently high enough to just do a replacement in older air conditioners. This is why it’s so important to shut off the air conditioning and call a reliable HVAC company if you hear hissing sounds coming from the compressor.

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