Are you looking to find out how to test a dryer thermistor with a multimeter? A thermistor is an important part of many appliances, like your dryer. It’s responsible for controlling the temperature and keeping it within safe limits. Testing a dryer thermistor can help ensure optimal performance from your appliance and avoid potential damage down the line. In this blog post, we’ll explain how to use a multimeter to safely, accurately, and easily test a dryer thermistor!
What does the thermistor do on the dryer?
A thermistor in a dryer is a temperature-sensing component that plays a crucial role in regulating and controlling the temperature inside the dryer. It functions by changing its electrical resistance in response to changes in temperature. Here’s how it works:
The thermistor is strategically placed within the dryer’s heating system, typically near the dryer’s exhaust or air intake. It constantly measures the air temperature or the heating element inside the dryer.
As the temperature changes, the thermistor’s electrical resistance changes proportionally. When the temperature rises, the resistance decreases, and when it cools down, the resistance increases.
Control and Safety:
The dryer’s control system continuously monitors the thermistor’s resistance values. The control system uses this data to regulate the heating element’s power or turn it on and off to maintain the desired temperature for drying clothes.
In addition to temperature control, thermistors also serve as a safety feature. If the dryer’s temperature rises abnormally, indicating a potential overheating issue, the thermistor can trigger a safety mechanism to shut off the heating element or the entire dryer to prevent fires or damage.
A thermistor in a dryer helps maintain consistent and safe drying temperatures, ensuring that your clothes are dried effectively without overheating, which can be energy-efficient and prevent damage to your garments.
Tools and Equipment Needed:
A multimeter is an electronic measuring instrument that measures various electrical properties, including voltage, current, and resistance. It typically has a digital display and probes that you use to make electrical connections and take readings.
Screwdrivers are hand tools with a handle and a metal shaft that ends in a tip of various shapes (e.g., flathead, Phillips, Torx). They are used to turn screws commonly used in appliances to hold components together.
Needle-nose pliers are a type of pliers with long, thin jaws that taper to a point. They are used for gripping, bending, and manipulating small objects, wires, or components, making them useful for disconnecting wires.
Safety gloves are protective hand coverings made from materials designed to shield your hands from sharp objects, heat, or electrical hazards. They ensure your hands are safe while working with potentially dangerous equipment.
Safety glasses are eyewear designed to protect your eyes from debris, flying particles, or potential hazards. They provide an extra layer of protection for your eyes during repair work.
Workbench or sturdy surface:
A workbench or a sturdy surface is a flat, stable area where you can safely perform your repair work. It provides a secure and organized space for disassembling and reassembling the appliance.
Replacement thermistor (optional):
A replacement thermistor is a spare or new thermistor that you may need if the original thermistor in your dryer is found faulty during testing. It replaces the old one to ensure the appliance operates correctly.
These tools and equipment are essential for safely and effectively testing and, if necessary, replacing a dryer thermistor. They help ensure the appliance functions properly and the repair work is conducted safely and efficiently.
How to Test a Dryer Thermistor
Access the Thermistor
- Ensure the dryer is unplugged or disconnected from its power source for safety.
- Access the thermistor inside the dryer near the heating element or exhaust vent. You may need to remove panels or access covers to reach it.
Disconnect the Wires
- Carefully disconnect the wires from the thermistor. Take note of which wire goes where to reconnect them correctly later.
Set Your Multimeter
- Turn on your multimeter and set it to measure resistance (Ω). Refer to your multimeter’s user manual if you’re unsure how to select the resistance measurement mode.
- Ensure the multimeter is set to measure within an appropriate range. Most dryer thermistors at room temperature (around 77°F or 25°C) have a resistance of around 10,000 ohms, so select an appropriate range that covers this value.
Measure the Resistance
- Touch the multimeter probes to the two terminals of the thermistor. It doesn’t matter which probe goes where.
- The multimeter will display a resistance reading. Note down this reading.
Interpreting the Resistance Reading
- Compare the resistance reading you obtained with your specific thermistor model’s expected or specified resistance value. You can typically find this information in the dryer’s service manual or on the thermistor itself.
- If the resistance reading is close to the specified value, the thermistor is likely functioning correctly.
- If the resistance reading significantly differs from the specified value, it may indicate a faulty thermistor that needs replacement.
Repeat the Test
- If you have any doubts about the accuracy of your measurement or if the thermistor’s resistance reading is borderline, you can repeat the test to confirm the results.
- If the repeated measurements consistently show a significant deviation from the specified resistance value, it strongly indicates that the thermistor is faulty and should be replaced.
Following these steps, you can effectively test your dryer’s thermistor to determine if it’s functioning correctly or needs replacement. This can help diagnose and resolve temperature-related issues in your dryer’s operation.
Symptoms of a Faulty Thermistor
A faulty thermistor can manifest in various ways, impacting the performance of your dryer. Look out for these common symptoms:
- Clothes are not drying properly or taking longer than usual to dry.
- The dryer is overheating or shutting off unexpectedly.
- Inconsistent temperature control during drying cycles.
- Error codes displayed on the dryer’s control panel related to temperature or sensor issues.
Replacing a Faulty Thermistor
If testing confirms that your thermistor is faulty, it’s time to replace it. Here’s how:
Order the Correct Replacement Thermistor
Refer to your dryer’s manual or consult an appliance parts store to find the correct replacement thermistor for your specific make and model.
Disconnect Power Supply
Before proceeding, unplug your dryer from the power source once again to ensure safety during the replacement process.
Remove Old Thermistor
Using a screwdriver, remove any screws securing the old thermistor in place. Carefully disconnect any wiring connections and remove the faulty thermistor from its mounting location.
Install New Thermistor
Attach the new thermistor in place of the old one, ensuring it is securely mounted. Reconnect any wiring connections following proper orientation and secure them as necessary.
Carefully reattach the access panel you removed, ensuring all screws are tightened securely. Double-check that no wires are pinched or obstructed during reassembly.
By learning how to test your dryer’s thermistor using a multimeter, you have gained valuable knowledge about an essential component responsible for regulating the temperature in your appliance. Armed with this information, you can troubleshoot potential issues, accurately diagnose problems, and take appropriate action, such as replacing a faulty thermistor. Remember to prioritize safety throughout the process and consult professional help if needed. With a properly functioning thermistor, your dryer will return to quickly drying your clothes.
FAQs about How to Test Dryer Thermistor
While using a multimeter is the most accurate way to test a dryer thermistor, it is possible to perform basic visual inspections for any signs of damage or malfunction. However, this method may not provide precise results.
If your thermistor tests within the acceptable range, but you’re still experiencing issues with your dryer’s performance, it’s advisable to consult a professional technician who can conduct further diagnostics and identify any other underlying problems.
Yes, different dryer models may use varying types of thermistors based on their specific design and technology. It’s crucial to ensure you are using the correct replacement part for your particular make and model of dryer.
Replacing a faulty thermistor can be done as a DIY project if you have basic knowledge of appliance repairs and follow proper safety precautions. However, if you are unsure or uncomfortable working with electrical components, it’s always best to seek professional assistance to avoid any potential hazards or further damage.
Continuing to use your dryer if you suspect a faulty thermistor is not recommended. A malfunctioning thermistor can affect the appliance’s temperature control, potentially leading to overheating or other safety hazards. It’s best to address the issue promptly.
Testing the thermistor is typically done when you notice performance issues or suspect a problem. There’s no need for routine testing unless your dryer manufacturer recommends it in the user manual.
Yes, a malfunctioning thermistor can lead to various dryer problems, including a complete shutdown. It’s one of the components that help regulate the appliance’s temperature, so it can disrupt the drying process when it fails.
Absolutely. Always disconnect your dryer from the power source before testing or repairing it. Additionally, wear safety gloves and goggles to protect yourself from potential electrical hazards.
Signs of a faulty thermistor can include clothes not drying properly, unusual temperature fluctuations, extended drying times, or error codes displayed on your dryer’s control panel. If you notice any of these symptoms, it’s worth checking the thermistor.
No, cleaning the thermistor is not recommended. If it’s malfunctioning, cleaning won’t resolve the issue. It’s best to test and replace it if necessary or seek professional assistance.
My name is Robert Phillipson, and I am an Electrical Engineer with 20 years of experience in the field. My fascination with multimeters began early on during my career as I was captivated by their precision and accuracy. Over the years, I have gained a deep understanding of how they work, enabling me to use them effectively for measurement applications like testing circuit boards and other components.