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How to Find the Right Capacitor Size

How to Find the Right Capacitor Size

Think of your AC's capacitor as a battery to keep the motor running. Just like batteries, the brand name or model number does not matter, what matters is how much power it can supply. In this guide we will walk you through how to safely determine what kind of capacitor you need for your system.

Required Tools

  • Drill or hex screwdriver
  • 1/4" or 5/16" Hex Head
  • Needle nose pliers
  1. Turning off the power - Safety is always first. Start by locating the power switch for your unit. In most cases, units are connected directly to the breaker box in your house. However, some units have a separate breaker box located outside near the system. Also, if you have a split heating and cooling system, there may be a switch, fuse, or breaker for each system. Once you have located the appropriate switches, turn them off before touching your unit.
  2. Opening up the unit - Time to bust out your drill and open up the service panel on your unit. In most cases, it will be directly above the unit's refrigeration line.
  3. Locating the capacitor - The capacitor will be attached to the side of the unit in a bracket near the control board, you can loosen this bracket and slide it out to see your capacitor. Use your pliers to pull off the connectors.
  4. Reading your capacitor - Okay, you should now have your old capacitor in-hand. Look for a label on the side, specifically, you are looking for two values: the MFD/uF and the VAC/V. MFD or microfarads shows the storing capacity of the capacitor. VAC stands for volts alternating current, indicating the speed of the electrical current through the capacitor. Think of these values like the battery ratings on normal batteries, if your device needs a AA, you get a AA battery. The same applies here.
  5. Unreadable capacitors - If it has been a while since your unit has been serviced, the label may have worn away or may be covered by rust. In that case, we can help. All you have to do is write down the model number of your AC unit, and include it in this form. We will match your system to the right capacitor and send you a quote for the replacement.
  6. Reconnecting the capacitor - Depending on the type of capacitor you have, there will be 2 or 3 connection terminals on top. If there are 3 terminals, each should be labeled with FAN, HERM, or C. If you cannot read them, the FAN terminal will always have 2 tines, the HERM terminal will always have 3 tines, and C will always have 4 tines. If there are only 2 terminals, they should have the same number of tines. Match the wires to the appropriate terminals by counting the tines. 

You can see a list of all our capacitors we offer here.

Also, if you cannot find the right capacitor for you, give us a call!  We may have it unlisted in our warehouse, and if not, we are always happy to special order parts for our customers.


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