Video: Range Hoods: Basic Knowledge and Analysis of Related Common Problems
Figure 1: Range hood.
Range hood, also known as extractor hood, is a kitchen appliance that purifies the kitchen environment. It is
installed above the kitchen stove. It can quickly remove the waste burned by the stove and the harmful oil fumes
generated during the cooking process, and discharge them outdoors, reducing pollution, purifying the air, and
providing anti-toxic and explosion-proof safety guarantees.
When purchasing any product, it is best to study its internal structure. First, knowing its structural composition,
you will know why something is more expensive or cheaper. Secondly, it can also pave the way for future use and
maintenance.
So today we will talk to you about the internal structure of the range hood, introduction to its various parts,
working principle and solutions to common related problems.
1. Basic Structure and Working Principle of Range Hood
The basic structure and working principle of the range hood are introduced below.
1.1 Basic Structure of Range Hood
All components of the range hood are mainly supported by the box. The box is equipped with air deflectors and panel
components. The volute casing, motor, fan wheel, check valve, lights and other components are installed
inside the box.
1. The motor is the key component of the range hood, consisting of the stator, rotor, front and rear covers,
bearings, etc.
2. The fan wheel is responsible for the smoke suction and exhaust. It is mostly a centrifugal fan wheel.
3. The upper part of the volute casing is connected to the check valve and the lower part is connected to the air
deflector. The main function of the volute casing is to allow the oil fume sucked by the fan wheel to be discharged
smoothly, and at the same time, the fan wheel throws the condensed oil onto the volute casing to facilitate the
collection of oil.
4. The check valve connects the volute casing and the exhaust duct and can prevent backdraft.
5. The air deflector and the panel are combined to form the oil smoke collecting hood.
Figure 2: Centrifugal blower.
1.2 Basic Working Principle of Range Hood
After the power of range hood is turned on, the motor drives the fan wheel to rotate at high speed, causing an air
pressure difference between the inside and outside of the air inlet and the exhaust vent of the range hood, so that
the oil smoke can rotate and accelerate with the air in the volute casing and be blown outdoors.
At the same time, during the process of discharging oil fumes, some high-temperature oil particles in the oil fume
are thrown to the inner wall of the volute casing under the centrifugal force of the fan wheel. After condensing
into oil droplets, they flow back to the oil collecting device under the action of gravity.
Figure 3: Working principle diagram of range hood.
2. Common Problems and Solutions Related to Range Hoods
With the continuous improvement of living standards, range hoods have become more and more indispensable in daily life. It is inevitable that we will encounter problems with range hoods during daily use.
2.1 Range Hood Motor Buzzes and Fan Does Not Spin
Analysis of the reasons why the range hood buzzes when it is turned on and the fan does not spin:
1. The internal capacitor of the range hood is damaged or
the capacitance is reduced.
2. The hygiene is not done well, resulting in excessive oil stains inside the range hood.
3. There is a short circuit in the coil inside the range hood.
4. The bearings of the range hood are out of oil.
5. The fan impeller in the range hood has been deformed or aged.
Suggested solutions:
1. If the capacitor is damaged or the capacitance is reduced, it needs to be replaced with a new capacitor of the
same model.
2. To remove oil stains on the range hood every once in a while, you can use cleaning agents such as soda water and
dish soap.
3. The range hood coil is short-circuited, usually because the range hood and other large appliances share a socket,
causing the household circuit to be unable to support the operation of the range hood. At this time, you only need
to disconnect other electrical appliances. If the coil is burned out, you need to contact the after-sales department
to replace it with a new one.
4. The bearings in the range hood will accumulate dust continually. When it reaches a certain level, the bearings
will become stuck due to lack of lubricating oil. You can use your hands to turn the bearing to see if it is smooth.
If it is not smooth, you need to clean off the dust, and then add lubricant to make it run smoothly.
5. If the fan wheel is deformed, a large amount of oil will adhere to it, causing the fan wheel to become unbalanced
and the fan will not rotate.
Try to clean the fan wheel and then reinstall it. However, if it still does not operate normally, you must replace
the fan wheel with a new one. This process requires the after-sales department to come to replace it.
Figure 4: Air flow in a range hood.
2.2 Why is the Range Hood Fan Shaking?
There may be many reasons why the range hood fan is vibrating. Here are some common causes and solutions:
1. Damaged fan blades: If there is obvious noise and vibration when the range hood fan rotates, the
fan blades may be damaged, causing imbalance. At this time, the fan blades need to be replaced.
2. Aging of fan bearings: If the range hood is used for a long time, the fan bearings are prone to
aging, resulting in unstable rotation and even vibration. At this time, the fan bearing needs to be replaced.
3. The installation is not firm: If the range hood fan vibrates during operation, it may be that
the installation is not firm enough and needs to be reinstalled.
4. Motor failure: If the motor of the range hood fan fails, it will also cause vibration. In this
case, the motor needs to be replaced.
5. The air duct is blocked or bent: If the air duct of the range hood is blocked or bent by foreign
objects, the fan will be blocked and vibrate during operation. At this time, you need to clean the air duct or
change the layout of the air duct.
Figure 5: Double motor range hood fan wheel.
2.3 Range Hood Fan Not Working but Light is?
If your range hood fan is not working while the light is functional, it could be due to a faulty fan motor, a malfunctioning switch, or wiring issues. Check the power supply, inspect for visible damage, and test the motor's continuity with a multimeter. If the motor is fine, examine the switch and wiring for defects. If troubleshooting doesn't resolve the problem, consulting the user manual or seeking professional assistance may be necessary for further diagnosis and repairs.
2.4 How to Replace the Fan of Range Hood?
Steps to replace the fan of range hood:
1. Prepare tools and materials: a new range hood fan, screwdriver, etc.
2. Turn off the power, use a screwdriver to remove the cover of the range hood, find the original fan and remove it.
3. Place the new fan into the range hood and keep it connected to the air duct.
4. Connect the original wires to the new fan wires. Make sure the wires are firmly connected and not loose.
5. Return the range hood cover and tighten it with a screwdriver.
6. Turn on the power and test whether the newly installed fan is normal.
Notice:
1. Before replacing the fan with a new one, wipe away the dust and dirt around it.
2. Before replacing, you need to cut off the power supply to avoid safety hazards.
3. Before connecting the wires, check whether the new fan wires meet the standards.
4. When replacing the fan, you can first remove the old fan and check the model to ensure that the new fan is
consistent with the old one.
In short, replacing the fan of the range hood is not difficult. As long as you are well prepared and follow the
steps, you can easily complete it. If you encounter problems during the replacement process, please ask
professionals for assistance in time.
Figure 6: Range hood replacement fan.
2.5 How Often Should the Range Hood be Cleaned?
The kitchen range hood needs to be rubbed once a day after use to remove the grease. The filter screen generally needs to be cleaned every 5 to 10 days. The range hood fan needs to be cleaned every 3 months to 6 months. If the range hood is used more than a year, an overall deep cleaning is required by a professional. If there is a lot of oil smoke, the cleaning cycle should be shortened to reduce the load on the machine, eliminate hidden dangers, and make it work better.
Figure 7: Clean range hood.
2.6 How to Clean Range Hood Fan Motor?
To clean a range hood fan motor, start by turning off power and removing the fan assembly. Use a degreaser to clean the fan blades and motor housing, ensuring it's completely dry before reinstallation. Avoid soaking the motor or using excessive water. Reassemble the fan and ensure it's dry before restoring power. Regular maintenance prevents excessive dust and oil buildup and ensures efficient operation.
2.7 Which is More Effective, Range Hood or Exhaust Fan?
Of course, a range hood is better. First, let’s take a look at the differences between the two:
1. Power: The power of the range hood is 100-300 watts, most of which are about 200 watts, while
the power of the exhaust fan is much smaller than that of the range hood, usually about tens of watts, and generally
not more than 100 watts, so the effect of exhaust fan is not as good as that of a range hood.
2. Function: The main function of the range hood is to extract oil smoke and discharge it outside
the kitchen. Although the exhaust fan also has a smoke exhaust function, its main function is to keep the air indoor
fresh and provide ventilation.
3. Conclusion
The above is an introduction to the basic knowledge and common problems related to the range hood. When encountering a range hood failure, if you cannot solve it yourself, do not disassemble the range hood at will to avoid causing irreversible damage to it. If you encounter more complex problems, it is recommended to find professionals to ask for help.
