Blowing the fuse cuts the power to the unit to prevent electrical damage. If your AC has shut down and won't start again, especially if you've noticed odd electrical behavior immediately before the shutdown, chances are the fuse has done its job and will need to be replaced.
Fuses play a vital role in maintaining the overall integrity of the AC system, ensuring its safe and reliable operation while also safeguarding against potential fire hazards that could arise from electrical failures. If the AC fuse blows, your air conditioner won't turn on.
If you have fuses, you can only reset the AC by taking the fuse out. After the 30 minutes lapses, reinstall the fuse back in position if it's still in good condition, but replace a worn-out fuse with a new one. Now turn the AC back on, confirm if the thermostat is set to cool, and observe how the unit functions.
If you think your air conditioner has blown a fuse, the first sign you'll notice is that the outside AC unit is inoperable. The best way to check for a blown fuse is by using a voltmeter. Be warned — you are working with live electricity and should use extreme caution when troubleshooting your system.
In AC systems, the air conditioner reset button is on the outside unit's lower edge, typically close to the ground. Some models have the reset button located behind the service panel, which may require tools to remove. Reset buttons are usually red or yellow with a clear “reset” label.
Check the thermostat
You should check if it's been set to the correct temperature and also make sure it's set to “cool”. If the AC settings are not right, it won't turn on. You can also check if the batteries in the thermostat are fresh and replace them if needed.
In most cases, the small red reset button is inside the AC's compressor. If unsure, you can always refer to the user's manual to find the exact location.
It's important to be able to recognize the signs. If your device suddenly stops working, it could be a blown fuse. Check for discoloration or markings on the fuse. If you see any damage, there's a good chance the fuse needs to be replaced.
AC Fuse, Circuit Breaker, or Relay Replacement Cost
Expect to pay between $15 and $300 to have AC fuse and circuit breaker issues addressed or relays in your AC unit replaced. These projects do not usually take more than a couple of hours.
Fuses for protecting HVAC equipment are typically cylindrical cartridges that snap into fuse holders inside the manual disconnect box. They're opaque, so when one blows you may not be able to tell by looking at it. You can test for a blown fuse with a multimeter, or do as some people do and simply replace it.
Wear and Tear on the Fuse
The lifespan of a fuse can be up to 20 years. AC fuses are usually what is known as 'slo-blow' or 'time delay' fuses. This means that they are at work every time you turn the machine on and off and eventually, will simply wear out due to the strain of the operation.
For AC capacitor replacement, anticipate spending between $150 and $400, depending on the capacitor's type and accessibility. A bad AC capacitor is a fairly minor repair, and most HVAC technicians will recommend a repair rather than replacing the unit when the capacitor is the problem.
There have been many breakdowns and even fires over the years caused by issues with disconnects. Make inspecting them a regular part of your maintenance and service call process, and you can save some issues.
Check Your Circuit Breaker
Locate your main circuit breaker and switch it back to the "On" position. Wait 30 seconds and turn on your air conditioner again. If it still doesn't work, you'll need to call a professional for help.
Make sure the outside unit is turned on (there's probably a switch near the unit). If the outside unit has a separate circuit breaker, check your circuit box and make sure it hasn't been tripped. A more serious issue if the outside air conditioning unit's not working is a broken compressor, capacitor or fan.
The AC fuse on most HVAC systems is typically on the unit's control board. You'll normally find the board behind an access panel on the unit's lower compartment. While you sometimes have to unscrew areas to access the control board, others have clips.
Not all air conditioning units have a reset button, but if yours does, it's typically located on the outdoor unit. Here's how to locate it: Turn Off the Power: Before you search for the reset button, ensure the power to the unit is turned off for safety reasons.
Use the Reset Button on AC Unit
Don't worry; the reset button might be able to solve the issue after a sudden disconnection or power outage. You can press the “Reset” button on the air conditioning unit, often shown as a small red button, to bring your air conditioning unit back to life.
This issue is when a circuit breaker powers on, protecting your appliances from voltage hazards. Sometimes, after a breaker is tripped, your AC unit may not work as well as before. If you have it set at a cool temperature but all you're feeling is warm air — a quick reset is sometimes all you need.