A hissing noise from the freezer is often normal. It’s of concern if it does it for long periods. Knowing the causes of the sound can help you determine whether or not it’s an issue requiring the assistance of a professional. In many cases, it’s nothing more than a nuisance, as it won’t affect the performance of the freezer in any way.
The three causes of “freezer making hissing noises” due to:
- The Freezer Defrosting
- Thermostatic Expansion
- A Punctured Hole in the Coil
Each comes with its level of concern. Some are more alarming than others. Being informed about the make, model, and inner workings of your freezer can help keep it in good working order long-term.
This guide breaks down the three most common sources of the hissing sound you’re hearing come from your freezer. It helps you understand why the appliance is making a noise. It also helps you better understand which steps to take next if the sound doesn’t go away.
Freezer Hissing Cause 1: Defrost Cycle
So, what makes the hissing noise in the defrost cycle? That’s an excellent question to ask. To help you better understand why it occurs, it’s first important to go over what the defrost cycle entails and why it’s necessary.
In general your fridge or freezer is either frost free or manual defrost. If you are hearing the hissing noise from your refrigerator and you own a frost free unit this very well could be the cause. In order to check if your unit is frost free find your product # and google it.
The purpose of a freezer is to keep food from spoiling by allowing it to remain a temperature below freezing and preserving its flavor and texture. The defrost cycle exists to remove frost from the evaporator coils so that ice doesn’t build up inside the unit. When the evaporator gets covered in frost, it cannot maintain the cold temperature the freezer needs to keep the food inside of it from spoiling.
The hissing can be a result of the the heater element turning on and melting the water. The water as it melts off of the evaporator coils might drip onto the element producing the hissing noise.
Freezer Hissing Cause 2: Thermostatic Expansion
Thermostatic expansion occurs in a valve meant to control the flow of refrigerant in a freezer. The reason why it is needed is that it controls the load inside the evaporator. Load size determines the flow of refrigerant with the compressor going down 33 or 25 percent capacity being of concern, according to Science Direct.
When the load is high, there is more refrigerant flowing through the valve. When the load is low, there is less refrigerant passing through. The purpose of the part is to keep the freezer’s compressor working optimally so that the refrigeration portion of the appliance does what it is supposed to do.
The hissing sound that you’re hearing can be due in part to the expansion of the thermostatic valve as it passes the refrigerant through. It’s a normal process and one that shouldn’t be of concern to you. It doesn’t indicate that anything is wrong, but instead, it is part of the normal cycle a freezer goes through.
Freezer Hissing Cause 3: Punctured or Leaking Coil
If you puncture an evaporator coil or condenser coil, the hissing noise will be due to the refrigerant, aka gas leaking. Other wise known as a “freon leak”. To better understand why it’s an issue, we’ll explain where to find the evaporator and condenser coils, and ways to patch a puncture. Doing so can prevent you from losing your freezer entirely and risk the contents inside from spoiling because they got too hot.
Evaporator Coil Location
The evaporator coils are inside the freezer most typically at the back behind an access panel. To access them, you’ll need to remove everything from your freezer and then unscrew the panel. There are chances that if you have an older model or mini fridge that the evaporator is exposed or makes up the freezer compartment (which is why it get punctured).
Condenser Coil Location
The condenser coils are most commonly found in three places, the first being at the rear and bottom of the fridge. You might need to remove a back panel but chances are when you pull the fridge/freezer out you will be able to see them. They might be copper color, black, or event grey. The second place is running up and down the back of the unit (typical on older fridges). The third place is behind the front kick plate. In order to access them normally you can un-clip the plastic panel and you will be able to see them.
How to Fix the Puncture or Leak
Do not try to fix the hole or leak with duct tape. The best solution for fixing a leak in your condenser coils or evaporator coils is to turn of your unit after the leak is located.
The repair that is needed it highly dependent on the type of material that the damaged part is made of. For example if it is copper you might be able to silver solder it. It is aluminum it will have to be taken out and tig welded.
The best thing to do is to call an expert.
There are multiple reasons why your freezer is hissing, as mentioned above. Determining which is the leading cause of the sound that you’re hearing is imperative. It helps you better understand what you can do to correct it if a repair is necessary.
In most cases, it’s a normal sound that occurs while the freezer is in defrost mode. If it occurs after you’ve chipped away ice, it could be due to you puncturing the coil. That signifies trouble for your freezer and something you’ll need to address right away to keep your food from spoiling.
Contacting a professional with your request for service may be one option to save your current freezer from meeting its demise. If there isn’t much to do to fix it, you’ll need to purchase a new freezer. Until it arrives and you have a professional install it, you’ll need to keep your frozen food in an ice chest covered with ice to keep the temperatures from rising.