How to check the thermal fuse with a multimeter
Content
Thermal fuses often blow due to power surges and sometimes due to clogging. You can't just look at a fuse and see if it's blown, you need to do a continuity test.
A continuity check determines the presence of a continuous electrical path. If the thermal fuse has integrity, then it is working, and if not, then it is faulty and needs to be replaced.
This article will describe a few simple steps to check if a fuse has a continuity circuit or not. To do this, you will need a multimeter, preferably a digital multimeter.
For testing, you need to follow these steps:
1. Locate and remove the fuse from your appliance,
2. Open the thermal fuse without damaging it or hurting yourself, and finally
3. Set the multimeter to the correct mode to test for continuity.
Required Tools
You will need the following equipment to test fuse continuity:
- Functional digital or analog multimeter
- Thermal fuse from a faulty appliance
- Connecting wires or sensors
- Electrical appliance
- Screwdrivers of different sizes
How to check a fuse with a multimeter
Follow the steps below to understand what you need to do to find out if your fuse is in the proper condition.
- Location and removal of the thermal fuse: Thermal fuses are available in various shapes and sizes. They all have the same internal functions that define their functionality. For example, if you are using a dryer, you would start by removing all screws and looking for a thermal fuse. Then shunt the wires and remove the fuse. The fuse labels help us to make sure that the appliance is not connected to a power source. This helps us avoid electric shock. Most fuses are securely fixed in the access panel. They are installed behind the display or control panel (for example, in a microwave oven or dishwasher). In refrigerators, thermal fuses are present in the freezer. It's behind the evaporator cover because of the heater. (1)
- How to open the thermal fuse without damaging it or injuring yourself: To open the fuse, disconnect the wires from the terminals. Then use a screwdriver to remove the screws holding the thermal fuse in place.
- How to Prepare a Multimeter for a Continuity TestA: Before you can decide whether to replace the old fuse or not, you need to perform a continuity test. You will need a multimeter for this task. Sometimes fuse terminals get clogged. Therefore, you may need to unclog the blockage by removing blockages or dirt. Then gently rub them with a metal object before conducting a continuity test. (2)
To tune the multimeter, turn the range dial to the lowest resistance value in ohms. After that, calibrate the meters by connecting the sensors together. Set the needle to zero (for an analog multimeter). For a digital multimeter, turn the dial to the minimum resistance value. Then use one probe to touch one of the instrument's terminals and the other probe to touch the other terminal.
If the reading is zero ohms, the fuse has integrity. If the hand does not move (for analog) or if the display does not change significantly (for digital), then there is no continuity. Lack of continuity means the fuse is blown and needs to be replaced.
Replacing a defective fuse and maintenance tips
To replace the thermal fuse, reverse the removal procedure as above. To reduce the risk of blowing fuses, use voltage regulators to delay power or voltage. To reduce clogging, it is necessary to close the fuse and fill the holes in the device. Finally, use a permanent fuse.
Take a look at some of our articles below.
- Multimeter continuity symbol
- How to read ohms on a multimeter
- How to test a capacitor with a multimeter
Recommendations
(1) electric shock - https://www.sciencedirect.com/topics/medicine-and-dentistry/electrocution
(2) metal object - https://www.britannica.com/science/metal-chemistry
