Good day steemians!

This is my second tutorial on rice cooker. My previous tutorial on rice cooker is more about determining the basic problems commonly encountered on rice cooker. You can check my last tutorial at:
https://steemit.com/tutorial/@thinkingmind/exploring-electric-rice-cooker-or-part-1-diagnosing-simple-and-common-problems-that-occurs-on-a-rice-cooker

This tutorial focuses only on a problem regarding with thermal fuse. This is my personalized tutorial and these steps are based on my personal experience. Hope you will like it and find it educational.

Overview of this Tutorial

What is a thermal fuse?

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Thermal fuse is a device used to prevent appliances from overheating. A thermal fuse is different from a thermal switch. They are triggered by temperature but, they differ in action. A thermal switch resets itself automatically when the temperature is beyond its limit. While, a thermal fuse is more like an electrical fuse that melts as temperature surpass the limit and need to be replace.

How it works?

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Is it made of two metal pieces which are attached together designed to melt down at a set temperature. At normal circumstances, the current flows through the combined metals. When its getting too hot, the material that holds the two metal plates together will melt down and separates the metal plates disallowing current to flow through between metals. At the moment when the thermal fuse is blown or melted, there is no way to repair it. Fuses are not repairable, they are meant to be replace once broken.

Why should we use it?

Appliances that use heating element like coffee maker, dryers, heating cup and rice cooker have a temperature controller called thermostat. It keeps the heating element at right temperature by turning on and off. Thermostat will set off when temperature is getting hot, and will set on when temperature is below. But, what will happen if this thermostat malfunctions and won’t work? The machine will heat up excessively and can cause fire.

A thermal fuse is a safety device that cuts off the appliance from source when there is an excessive heat which is beyond the operation limit of the appliance. In short, it is a protection to every appliance. It melts itself just to be sure the appliance will not be damaged by the uncontrolled heat.

Materials Needed

1. Multimeter

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• Use to check either the fuse is broken or not.
• Use to check the connectivity of circuitry

2. Pliers

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Long nose pliers

• Use to hold pieces and splice wires

Side cutter pliers

• Use to cut wires

3. Screw driver

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• Use to loosen and lock screws

For your safety, these following must be observed

1. Unplug the rice cooker from power source
2. Do not use screw driver with broken handle
3. Do not use pliers as hammer it would likely results crack or break
4. Cut hard wires only with pliers
5. Cut the wires in right angle, do not rock side to side the wire or bend.
6. Do not replace thermal fuse with thin wires
7. Place back the insulator of thermal fuse after

Procedure on replacing the thermal fuse.

Step 1. Ensuring the rice cooker is not working

Step 2. Uncovering the rice cooker

Step 3. Locating the thermal fuse

Step 4. Getting the thermal fuse

Step 5. Testing the thermal fuse

Step 6. Replacing the thermal fuse

Step 1. Ensuring the rice cooker is not working

Before we try uncovering our rice cooker, let us make sure that it is not working. We can do this by testing the resistance of rice cooker when it is on and off. A good one changes its resistance as we “on” or “off” the appliance.

Connect the tester’s lead to the plug of rice cooker. Press down the switch to turn it on. As we can see in our tester display, it says “OL” means “over load” or simply saying there is no reading. Let’s differentiate between “no reading” and “zero reading”. No reading means that the circuit is not connected at all and zero reading means the circuit is shorted.

Connect again the tester’s lead to the plug. This time, release the switch. As we can see, there “no reading” also.

Based on the testing done, therefore, there is a problem with the rice cooker because there is no resistance reading when pressing and releasing the switch.

Step 2. Uncovering the rice cooker

Use screwdriver to loosen and unlock the screws. Bolted screws in rice cooker usually found under it. So, turn your rice cooker upside down and start loosening those screws.

Loosen the screws that attached the cover from the body.

Remove the cover.

Step 3. Locating the thermal fuse

Most fuses are found next to the AC cord and before the circuitry. It is intended to be place before circuitry because its main purpose is to protect them. In rice cooker, thermal fuse is usually next to ac cord and covered with rubberize sheath as its insulation.

Step 4. Getting the thermal fuse

Remove anything that attaches the fuse to the base, such as screws and bolts. Remove the rubberize sheath to reveal the fuse. Take extra care when removing fuse because it might tear the wire or anything attached to it.

Remove the screws that attach fuse to the body.

Remove anything that holds the fuse.

Remove the rubberize sheath to see the fuse.

This is the physical appearance of a thermal fuse.

Step 4. Testing the thermal fuse

Isolate the fuse to the body and ac cord for testing. Isolation should be done the avoid false reading. The tester might read the resistance of ac cord or the body itself. We conduct testing to ensure that the thermal fuse is really the problem.

Connect the lead of test to the fuse and observe the resistance reading.

Based on the reading, the fuse is not connected or current cannot flow through because it has no reading.

Step 5. Replacing the thermal fuse

When selecting thermal fuse to replace, make sure that it has the same parameters with the original thermal fuse. Voltage, current and temperature limit are the most important parameters to consider.

Reconnect the thermal fuse to the power line.

Reconnect the rubberize sheath. This will serve as the insulator for your thermal fuse.

Reconnect the screws and anything that attached or hold the thermal fuse.

Reconnect the screws and anything that attached or hold the thermal fuse.

Lock the screws.

Now, the rice cooker is assembled and ready for testing.

For testing:

Connect the tester’s lead to the plug. Press down the switch and observe the resistance.

Connect the tester’s lead to the plug. Release the switch and observe the resistance.

We see that it always has a resistance reading and it changes as we press the switch. Therefore, the rice cooker now is good.

Thank you for your time. Have a great day.

All pictures used in steps are mine @thinkingmind and taken from my phone camera.

Best wishes,

@thinkingmind

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