How To Troubleshoot And Replace A Failed Air Conditioning Fan Run Capacitor


If your air conditioner has ceased blowing cold air, then your compressor unit outside might have a failed run capacitor. When the capacitor fails, your HVAC system will only blow warm air.  

Run Capacitor Basics

A run capacitor is a cylindrical metal part with a red and a black wire attached to terminals on its top end. The capacitor's function is to store up extra electrical current to provide an extra jolt of power to start electrical components.

As capacitors fail, they slowly lose the ability to store power. The fan you can see spinning at the top of your air conditioner's compressor unit requires a capacitor to start it. If the capacitor fails, then the fan on your compressor unit will no longer be able to start. This failure causes the compressor to stop running as well because the fan is required to cool it.

Follow this simple procedure to determine if the run capacitor has failed on your air conditioner and replace it if that's the case.

Check the Status of the Condensor Unit's Fan

Before you turn off the power to the system, turn the air conditioning on at the thermostat and then go outside and watch the compressor unit. If the capacitor is bad, then the fan at the top won't be able to start. You will hear some clicking and then the unit will turn itself off. If this happens, then the capacitor needs replacement. If the fan comes on, then you need to call an HVAC contractor for further troubleshooting.

Turn Off the Power Supply and Let the Capacitor Discharge

It is important to note that while you can typically turn off the power and immediately start working on electrical problems, this is not the case with capacitors. Since capacitors store enough electrical charge to help start power-hogging parts like fan blades, they need a bit of time to discharge. For this reason, you should turn off the power to the air conditioner and then let it sit for a little while before you attempt to remove the faulty capacitor.

Replace the Run Capacitor 

Once the unit has sat for a bit, then you can transfer the two wires from the terminals on the top of the failed capacitor to the new one you purchased at a hardware store. The terminals are universal, so where you attach the wires doesn't matter as long as you attach one to each terminal. 

Turn On the Power and Test the Air Conditioner

Finally, once you have replaced the run capacitor, then you should turn back on the power and test to make sure you now have cold air coming out of the HVAC system. If the air is still warm, then you need to call an HVAC contractor from a company like Right Now Home Services for further troubleshooting.


23 August 2017

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Have you ever stopped to think about the general health of your air conditioner? Although it might seem like a silly thing to worry about, air conditioners need a little tender loving care just like any other home appliance. Unfortunately, it can be hard to detect issues until your system sputters to a halt one day. My blog is all about improving your HVAC experience by learning how to keep it on point. On my blog, you will learn how to check for air conditioning problems, troubleshoot your system, and even find the perfect replacement--should you need to upgrade your system.