When it comes to the defrost function, refrigerators can be divided into two main categories.
These two categories include self-defrosting and manual defrosting refrigerators, with most modern refrigerators today being self-defrosting.
There are two types of self-defrost systems. A time based defrost system (defrost timer) and a usage-based system, also known as an adaptive defrost system.
The time-based system launches the defrost cycle every after a certain period of time daily, while the adaptive system only initiates the defrost cycle when defrosting the fridge is actually needed.
In this article, we will explore the time-based system (defrost timer), what it is, how it works and so much more.
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Do all refrigerators have a defrost timer?
Most modern refrigerators are self-defrosting, which is also known as auto-defrosting.
Self-defrosting refrigerators that have a time based defrost system use a defrost timer to automate this process.
A defrost timer is very popular in entry-level or older refrigerators, and these are usually upright refrigerators.
There are also refrigerators that are manual defrosting and do not have a defrost timer. These require the fridge to be defrosted by an individual.
They are usually chest refrigerators, and most of such refrigerators are horizontal.
There are some chest refrigerators that have a defrost timer, but this is not very common. Just like there are some upright refrigerators that are manual defrosting but this is rare.
What is a fridge defrost timer?
A fridge defrost timer is a motor-powered clock device that effectively manages frost levels in a refrigerator and keeps the temperature in the fridge at a safe level.
There are two types of defrost timers. These are constant or continuous run defrost timers and accumulative defrost timers.
Constant or continuous run defrost timers operate constantly when a refrigerator is plugged in while accumulative defrost timers operate only when the refrigerator compressor is on.
Where is the refrigerator defrost timer located?
The refrigerator defrost timer can be found in various locations depending on the brand or model of the fridge.
Some common locations include the control panel or grille inside the freezer, or even in the compressor area in the rear of the fridge.
It can also be found behind the fridge’s lower kickplate, or behind the fridge on its back wall in some models.
Do modern refrigerators need defrosting?
Yes, modern refrigerators need defrosting, however, most do this automatically using a defrost timer.
Modern refrigerators still require defrosting because as the fridge keeps food cool, frost builds up which if not kept at safe levels could become excessive and cover the evaporator coils thus preventing air flow in the fridge.
There are still some refrigerators that require defrosting to be done manually.
This needs to be done by an individual whenever the ice level reaches a thickness of ¼ inches to ½ inches.
How do modern refrigerators defrost?
Most modern refrigerators are self-defrosting and come with an automated defrosting system that comprises 3 elements.
These elements include a defrost timer, a defrost thermostat and a defrost heater which all serve an important purpose in the defrost cycle
A defrost heater’s purpose is to provide the heat needed to melt the excess ice on the evaporator coils.
The defrost thermostat monitors the heat produced by the defrost heater and cues it to stop when the coils are back to an appropriate temperature.
A defrost timer manages and controls the levels of frost in a fridge by alternating the refrigerator between defrost mode and cooling mode.
It does this by turning each mode on or off accordingly at various intervals of time or when frost is detected. Neither mode is on at the same time.
The defrost mode is usually turned on every 12 to 15 hours for about 25 to 45 mins, and usually happens once or twice daily.
During the defrost cycle or mode, the compressor, also known as the fan or cooling function of the refrigerator is switched off and the defrost heater turned on.
Turning the defrost heater on leads to the evaporating coils being heated up, resulting in the frost melting.
The water from the melted ice then exits the refrigerator through a small passageway at the back of the fridge and pours onto a drip tray that is usually at the bottom.
As soon as the defrost cycle is done, the timer switches back to the cooling mode and the defrost heater is switched off.
In cooling mode, cold air circulates throughout the fridge resulting in condensation and the formation of ice which helps to cool down the fridge.
There are some refrigerators that use hot gas in the condenser to heat up the evaporator causing the excess frost to melt, and thus defrosting the fridge.
This system is usually found in commercial models like ice cream display freezers.
How do I manually turn on defrost timer?
In order to manually turn on a defrost timer, you will need a screwdriver.
This is because there is a space in all defrost timers where a flathead screwdriver can be inserted to manually control this device.
Before you begin, you need to check that the defrost timer isn’t actually on & operating already.
If it indeed isn’t already running, you can proceed and start by switching off the refrigerator.
When the screwdriver is inserted into the defrost timer and then moved in a clockwise direction, you will be able to manually open or shut the internal contacts of the device.
The first click that happens as the screwdriver is being moved indicates that the compressor is turned off and that the defrost heaters are turned on.
In turn, the second click indicates that the defrost heater is turned off and the compressor or the fan mode turned on.
Do all refrigerators have defrost timers? The answer to this question is both yes and no.
There are still some refrigerators on the market that do not come with a defrost timer, however, most modern refrigerators do include this feature.
Overall, defrost timers are amazing because they take away the time-consuming and labor-intensive inconvenience that the process of manual defrosting comes with.
So if you shopping around for a new refrigerator, ensure that the one you buy has auto-defrosting.