Anyone who has walked into their kitchen at night will have heard it - a series of strange pops and cracks emanating from the refrigerator.
Maytag refrigerators are known for being reliable, but minor issues occasionally arise. When the refrigerator starts making a clicking noise, there are several possible culprits. HELP -- My Frigidaire Fridge is Making a Loud Popping Noise. (BC, Canada) Four or five time. Loud Popping noise from refrigerator freezer wall NEW by: George I recently added Freon to my 10 yr old GE side by side do to not cooling properly (with all other systems functioning properly) then got night time loud popping noises from freezer side wall. Though it's working well. My Maytag refrigerator makes a loud popping noise. It woke me up at 1 am. Refridgerator is 10 years old no ice - Maytag MSD2756G Side by Side question.
The source of these loud knocks and groans has baffled manufacturers, who have sought fruitlessly to solve the problem.
But now scientists claim to have identified the source of the mysterious noises.
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The loud cracking noises from household fridges disturb up to half of households according to researchers
Using specialised sensors they found that the noises occur due to the contraction and expansion of the fridge components and panels as they change temperature.
This constant shape changing creates stress in the parts and over time they start to produce different noises depending on their size, shape and location.
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THE SCIENCE OF DISHWASHERS
Scientific research claims to have identified the definitive way to organise a dishwasher's racks.
By conducting the most detailed analysis of how water circulates inside a household dishwasher, the research has suggested that most people pack their appliance the wrong way.
While most users are constrained by the arrangement of the racks supplied with the dishwasher, the scientists who conducted the work say manufacturers should change their design.
They found that the most efficient way to pack your dishwasher is by putting plates in a circle.
They found that while the entire interior of the dishwater will get wet during a cycle, it will not necessarily clean everything in the same way.
The study also showed that the areas towards the edges of the dishwasher basket on the bottom shelf tend to be where water travels slower.
This means that the detergent will have more time to work on dishes in these areas, making them the ideal place to put egg and custard covered plates.
Plates with dried on carbohydrate like potato, however, are better placed in the direct line of the water jets.
The scientists hope their discovery can now be used to help engineers develop new designs that minimise this problem.
Loud cracking noises are particularly a problem in fridges that are designed to be frost-free.
Dr Hasan Koruk, a mechanical engineer at the MEF University in Istanbul who led the work, said this is because they have a heater that rapidly heats up during defrost cycles.
He said: 'The heater panel, which is very close to the heater and the most affected component from the heating is the main source of the cracks.
'The appropriate design of the heater panel and optimisation of the heating process to decrease the rapid temperature changes, and thus the contraction and expansion of structural components, can minimise the very annoying crack noises in the modern household refrigerators.'
Fridge noises are a common problem in homes around the world and generate regular complaints from consumers.
Around half of householders are disturbed by the noises their fridges produce, according to some surveys.
While most sounds, such as hums and whirring can be traced to the compressor or condensor fan inside the appliance, the random knocks and cracks that come from fridges have been a mystery.
The noises appear erratically and often without any pattern. Most consumers tend to notice them at night when they are at home and the household is at its quietest.
Running around the clock, the fridge is one of the hardest working appliances in our homes and in some cases the banging noise can be so loud it alarms users that something serious may be wrong.
The scientists measured the sound levels cracks produced by the fridges, seen as peaks in the graph above
The researchers found that rapid temperature changes in the plastic heater panel (shown in the diagram above) that sits in front of the anti-frost heater was the main source of the cracks as it changed shape
There have been a variety of theories for the cracking noise including the sound of ice that has built up on cooling plates breaking, but none have identified the source.
However, the new research, which is published in the journal Applied Acoustics, claims to have solved the problem.
By placing vibration sensors, microphones and temperature sensors were set up inside a specially modified refrigerator at the researchers had fitted to allow them to turn off different parts of the refrigerator while it was running.
This allowed them to isolate the source of the cracking noises. They found that the cracking seemed to appear whenever the heater at the back of the fridge was operated.
The cracking noises are more common in anti-frost fridges as rapid heating causes stress in the components
The researchers placed vibration (a), acoustic (p) and temperature (T) sensors around a fridge shown above
Dr Koruk said: 'The contraction and expansion due to rapid temperature changes create thermal stresses in the materials and eventually these burst type sounds occur.'
He said the vibrations created by the cracking noises were highest in the plastic heater panel that sits beside the heater.
He added: 'The heater causes the temperature of the heater panel to increase very rapidly at the beginning of the defrost process and its temperature decreases when also the defrost process is completed and the refrigerator starts to cool itself.
'Due to the rapid temperature changes, contraction and expansion create thermal stresses in the materials.'
Together with his colleague Dr Ahmet Arisoy, an engineer at Istanbul Technical University in Turkey, Dr Koruk has a solution to the problem.
They said that manufacturers can slow the heating rate to reduce the stress on the materials around it while they could also redesign the heating panel to include ribs and stiffeners that could dampen the sound it produces.
Dr Koruk said that a number of manufacturers have been in touch with them since they conducted the research to help them identify cracking noisees in their own appliances.
He told Mail Online: 'Unlike other home appliances, refrigerators operate all day and users respond sensitively to the noise they generate.
'The inhabitants are more annoyed with the unsteady fluctuating noises as compared to the steady operating noise.
'Especially, during sleeping hours due to natural decrease of the background noise, the high amplitude crack noise emitted by a refrigerator could be very annoying.'
A spokesman for the Association of Manufacturers of Domestic Appliances, which represents fridge makers,said: 'Fridge-freezers do make a variety of sounds in particular the frost-free models.
Refrigerator Makes Popping Noise Maytag
'Some manufacturers even supply an extra leaflet describing the noises that a particular appliance might make to reassure their customers that the sounds are normal for that product.
Maytag Refrigerator Loud Popping Noise
'The EU energy labels do include a noise rating and our members are aware that some customers do consider noise when choosing appliances.'