Why does the Fan make louder noises when you run certain programs, and is there a way to prevent it from making these loud sounds?

I would call bosch directly, they have ppl that can help over the phone with some things.... Bosch is hard to work on so if you need service I would go with who ever Bosch recemends..... ken

Your Acer Aspire, like any other desktop computer system, contains fans inside the case to help vent the heat generated by the internal components.
These fans generally operate quietly and reliably, working in the background to prevent your computer from overheating.
A fan that sounds excessively loud could indicate a problem such as overheating or loose internal components, or it could simply be a normally loud fan.
The key to differentiating between the two involves looking for additional clues from your computer.
Normal Operation
Due to computer configuration and build quality, the fans in some desktops sound louder than others.
Depending on what other brands of computers you've owned or have had experience with, the fan in the Acer may sound louder, when it's actually functioning perfectly.
The fan will run to keep the inside of the computer from overheating, so periodic runs are normal. If the fan runs for long periods or very often, you may have a deeper problem.

Fan Damage and Overheating
A fan can sound loud due to damage, such as broken blades or to a build-up of dirt that impedes normal operation.
This dirt, as well as normal wear and usage, can wear away the lubricant coating on the fan's internal shaft, causing the blades to make excessive noise as they turn. In many cases, a loud fan indicates that the computer is overheating, causing the fan to run more often than usual to try and cool the system.
Depending on the types of components and upgrades within your Acer computer, your current fan may be too small and weak to handle the heat output, and require upgrading to a larger, more powerful fan.


Troubleshooting Take note of when the fan turns on and how long it runs to determine any distinct patterns, whether if it occurs only during certain processes or programs.
Your computer's CPU generates a large amount of heat while in operation, so programs that require large amounts of CPU usage may trigger the fan more often.
Watch for additional signs of overheating, such as sudden shutdowns or computer crashes. Check inside the case for signs of other components touching the fan and causing vibration noise.

Solution

Do not overtax the CPU by opening numerous processor-intensive programs at once.
Check that all screws, cards and wires are securely fastened and away from the fan.
Keep your computer clean inside and out, to prevent the build-up of dirt on the fan blades or air vents and minimize the threat of overheating.
Apply a drop of oil to your fan's shaft to give it proper lubrication and smooth, quiet rotation of the blades.

http://www.techrepublic.com/article/quiet-noisy-computer-fans-with-a-drop-of-oil/5034842

Your Acer Aspire, like any other desktop computer system, contains fans inside the case to help vent the heat generated by the internal components.
These fans generally operate quietly and reliably, working in the background to prevent your computer from overheating.
A fan that sounds excessively loud could indicate a problem such as overheating or loose internal components, or it could simply be a normally loud fan.
The key to differentiating between the two involves looking for additional clues from your computer.
Normal Operation
Due to computer configuration and build quality, the fans in some desktops sound louder than others.
Depending on what other brands of computers you've owned or have had experience with, the fan in the Acer may sound louder, when it's actually functioning perfectly.
The fan will run to keep the inside of the computer from overheating, so periodic runs are normal. If the fan runs for long periods or very often, you may have a deeper problem.
Fan Damage and Overheating
A fan can sound loud due to damage, such as broken blades or to a build-up of dirt that impedes normal operation.
This dirt, as well as normal wear and usage, can wear away the lubricant coating on the fan's internal shaft, causing the blades to make excessive noise as they turn. In many cases, a loud fan indicates that the computer is overheating, causing the fan to run more often than usual to try and cool the system.
Depending on the types of components and upgrades within your Acer computer, your current fan may be too small and weak to handle the heat output, and require upgrading to a larger, more powerful fan.
Troubleshooting
Take note of when the fan turns on and how long it runs to determine any distinct patterns, whether if it occurs only during certain processes or programs.
Your computer's CPU generates a large amount of heat while in operation, so programs that require large amounts of CPU usage may trigger the fan more often.
Watch for additional signs of overheating, such as sudden shutdowns or computer crashes. Check inside the case for signs of other components touching the fan and causing vibration noise.
Solution
Do not overtax the CPU by opening numerous processor-intensive programs at once.
Check that all screws, cards and wires are securely fastened and away from the fan.
Keep your computer clean inside and out, to prevent the build-up of dirt on the fan blades or air vents and minimize the threat of overheating.
Apply a drop of oil to your fan's shaft to give it proper lubrication and smooth, quiet rotation of the blades.
http://www.techrepublic.com/article/quiet-noisy-computer-fans-with-a-drop-of-oil/5034842

It sounds like from the description when it is running the noise comes from the magnetron, some microwaves are louder than others, but this could be an early sign the magnetron is going.

Refrigerators are not the most complicated appliance in the house, but it still takes a lot of parts working together perfectly to keep your food cold. If one of those parts breaks down, or begins to, you may start to hear new noises from your refrigerator. Fridges make some noise during regular operation, but if it suddenly gets louder or makes a different noise, it is a good sign that something is wrong.

Freezer Fan
Freezers can be located on either side of the refrigerator, or may be at the top or the bottom of the unit. If you hear a noise coming from the area in which the freezer is located, you should open the freezer and see if the noise gets louder. Any squealing sounds coming from this area indicate a broken freezer fan. These units are not designed to be repaired, and eventually one making a loud noise will break and need replacement.

Condenser Fan
All motors typically require a fan in order to maintain a safe operating temperature. Like the fan in the freezer, the fan that runs on the condenser can also break down and create a similar squealing noise. The location of the fan noise is what differentiates the freezer and condenser fan problems. If you hear a fan noise coming from the lower part of the fridge at the rear, it is likely the condenser fan causing the problem.

Action to do
Open the freezer to see if the noise gets louder. If the noise becomes louder with the freezer open, the noise is likely caused by the evaporator fan. If the evaporator fan is the culprit, replace it to get rid of the noise.

Pull the refrigerator away from the wall, and check the condenser fan at the back of the fridge. A metal panel may cover the fan, which can be unscrewed. Listen to see if the fan is the source of the noise. If it is, the fan may need to be cleaned or replaced.

Thanks for using FixYa.

Good day ! : )

Unless it is really loud, the noise you describe is quite normal. Often, at higher speeds the whooshing of the blades will mask some of the motor sounds. we have found the Hunter fans to run the quietest.

Not sure what you mean by "heavy" and "loud"..

The fan might be "louder" because it may have been allot more quiet with the old failing fan clutch and not spinning fast enough.. Thus the new one working correctly making the fan spin much faster and being "louder"..
If that makes sense - to you question..

It is the bearing in the idler pully. about $35 and 30 minutes of work and its fixed.

take raer panel off inside freezer and check there is no ice build up which is hitting the fan

Have someone check the run capacitor of this unit. If the run capacitor is bad over shorted it can cause the unit to run and short cycle on a current overdraw. This makes for an electrical imbalance in the compressor motor. Next step is the compressor is faulty.