When a dryer buzzes but doesn’t start, most people assume the motor is bad. But that’s not always true. In many cases, the real problem is a failed start capacitor. This small part helps the motor kick in, especially under load. Without it, your dryer may hum for a moment, then do nothing. It’s frustrating, but it’s also something we can test. Understanding how the capacitor works, how to spot the symptoms, and how to check it safely gives you control. Our team at JAY Appliances handles this issue often during appliance repair in Edmonton, so we’ll walk you through the process in plain steps.
What the Start Capacitor Does in a Dryer
Electric dryers with split-phase motors rely on a start capacitor to boost torque at startup. It stores an electric charge and delivers it when the motor needs a push. That energy helps spin the drum and move air for heating. After that, the capacitor switches out of the circuit. Therefore, it only works at the beginning, but it plays a critical role.
If the capacitor fails, the motor may receive power but cannot turn. That’s when you hear the buzzing noise. It’s the sound of a motor under strain. In some cases, the dryer may start after several tries or when empty. But this isn’t safe to ignore, as it can lead to motor burnout. We often see this issue during dryer repair services in Edmonton, especially in older models or machines in dusty spaces.
Common Signs of a Faulty Start Capacitor
Buzzing is the most obvious symptom, but it’s not the only one. Dryers with capacitor trouble may stop suddenly during cycles. They may also take longer to start or only run when the drum is turned by hand. That’s because the motor lacks the initial force. In other cases, the breaker may trip due to the stalled motor drawing extra current.
Another clear sign is when the dryer heats but the drum doesn’t move. Since the heater and motor are separate systems, it’s possible for one to work and the other to fail. We’ve seen units where the lights and buttons work fine, but the drum just sits. These are all clues pointing to a bad capacitor, and it’s usually worth checking before replacing the motor.
Sometimes, a failed capacitor may also show physical signs. For example:
- A swollen or bulging case
- Burn marks or a burnt smell
- Leaking fluid or residue around the terminals
However, not all damaged capacitors look bad. That’s why we always test them using proper tools before jumping to conclusions. Diagnosing it the right way saves money and avoids replacing the wrong part.
How to Safely Test a Start Capacitor
Before opening the dryer, we always unplug it from power. Safety is non-negotiable. Capacitors can hold a charge even when the unit is off, so we discharge them using an insulated screwdriver with a resistor or a capacitor discharge tool. Never touch both terminals at once.
Next, we locate the capacitor, which is usually near the motor or inside a control panel. It’s a small cylindrical part with two or more terminals and a label showing its microfarad rating. Once removed, we use a digital multimeter with a capacitance setting.
To test:
- Set the meter to capacitance (symbol µF).
- Connect the probes to the capacitor terminals.
- Read the value and compare it to the label.
If the reading is far off (more than 10% deviation), the capacitor is bad. If it shows “OL” or no reading at all, it’s failed completely. In that case, we replace it with a part that matches both microfarads and voltage ratings.
We recommend using appliance repair in Edmonton for help if you’re unsure how to measure electrical components safely. Working around capacitors can be risky without experience, especially if you lack the tools.
Choosing the Right Replacement Capacitor
When a capacitor fails, the fix sounds simple—just swap it. But using the wrong one can damage the motor. We always match three key specs: microfarad rating, voltage rating, and physical size. The microfarad (µF) value must be exact, as it’s tied to the motor design. A mismatch may prevent startup or cause heat buildup.
Voltage should be equal or higher than the original. Using one with too low a voltage risks failure under load. Size also matters for fitting inside the dryer housing. We choose replacements from trusted suppliers and avoid parts with generic labels or unclear specs.
After installing the new capacitor, we reconnect the terminals, secure it in place, and test the dryer. Most times, the drum spins smoothly right away. But if the motor still hums, the problem might be deeper—such as a seized motor shaft or worn bearings. In that case, further diagnosis is needed.
This is a situation where professional support often helps. If you already tried a capacitor and it didn’t fix the issue, it may be time to contact a technician for appliance repair who can trace the wiring and check the motor directly.
Extra Tips to Prevent Future Failures
Dryers run hard in homes where laundry never stops. Heat, dust, and vibration wear parts over time. That includes the capacitor. While you can’t prevent all failures, a few habits help extend dryer life:
- Clean the lint filter after every load.
- Vacuum the vent and blower area every 3–6 months.
- Avoid overloading the drum, which strains the motor.
- Give the dryer time to cool between back-to-back cycles.
Capacitors wear down more quickly when they overheat or work harder than necessary. That’s why we often see repeat failures in units with poor airflow. By checking the exhaust and keeping the machine level, we reduce that stress.
During some dryer repair appointments in Edmonton, we install a new capacitor only to find it fails again in a few months. In those cases, the root problem is often overheating or a poor power supply, not just the part itself. Watching for these issues early saves long-term trouble.
FAQs
Why does my dryer only buzz but not start?
This usually points to a faulty start capacitor or a stuck motor. The buzzing means the motor is getting power but can’t turn.
Is it safe to test a capacitor at home?
It’s safe if you know how to discharge it and have a proper multimeter. Otherwise, it’s best to call a professional.
How do I know if I got the right capacitor?
Make sure the microfarad and voltage ratings match exactly. Physical size should also fit the mounting area.
Can I run the dryer without a capacitor?
No, the motor needs the capacitor to start. Running without it can damage other components.
What if replacing the capacitor doesn’t fix it?
The issue may be with the motor, switch, or wiring. It’s best to let a technician inspect it further.