How to Go from a Dual Capacitor to a Single in an Air Conditioner

By | July 4, 2023

How to Go from a Dual Capacitor to a Single Air Conditioner
If you have an HVAC system that has a single dual round capacitor, it can be split into two separate capacitors.

Two separate single capacitors can be installed when a dual round has failed.

First of all, I don’t suggest doing this, and it is only a quick fix when you don’t have the correct dual round capacitor with you.

With that said, this is done all the time by HVAC technicians, and you may find yourself working on a unit that has been fixed this way.

Wiring up two single capacitors is easy once understood that a dual round is two capacitors in one package.

A dual round capacitor shares the common leg while the other two leads are for the FAN and Compressor.

When swapped out for two single capacitors a jumper is added to add another common lead.

Both the MFD and voltage will be listed on the dual round.
How to Go from a Dual Capacitor to a Single Air Conditioner Read MFD
For example, the one listed in the picture above is listed as 35+5 MFD 440 VAC.

The higher 35 MFD number is for the compressor (Herm), and the smaller 5 MFD number is for the condensing fan motor (FAN).

The dual round capacitor can be replaced with two capacitors with the correct MFD and voltage.

Here is an example 3-wire HVAC dual round capacitor wiring diagram.
Example 3-wire AC dual capacitor wiring diagram
The common leg is shared, while Herm is the compressor, and Fan is the condensing fan motor.

Since a dual round shares the common leg there are only three connections. A jumper wire will need to go to the common leg on the added single capacitor.
How to Go from a Dual Capacitor to a Single Capacitor
Often what happens is one side will fail while the other is good, so an HVAC tech will simply wire a single to replace the bad side.

For example, most all dual rounds will have a capacitor for the compressor and one for the condensing fan motor.
How to Go from a Dual Capacitor to a Single Capacitor 2017
If the compressor side capacitor in the dual round is good, but the fan side fails, the fan side can be replaced with a single.

Since the compressor side capacitor is good, it will stay connected and working.

A Dual Round is two capacitors in the same package which can be separated into single units.

Wiring in a single capacitor to replace a dual is easy to do with some basic understanding.
How to Go from a Dual Capacitor to a Single
A jumper wire will need to be installed to carry the common wire to the added capacitor since a dual round will share this leg.

Also, be sure to match the MFD and voltages to the correct components.

Remember always install the correct components unless you have no other options.

Category: HVAC how to

About Aaron H. Benetti

Aaron H. Benetti an HVAC technician who has worked in the field since 1991. He began his career as an HVAC installer and later began doing troubleshooting and repairs. Around 2010, he began to write books on HVAC topics, mainly tutorials and how-to information. Currently, Aaron works as an HVAC tech and also writes many articles and posts for websites as well as books and videos on HVAC topics.

3 thoughts on “How to Go from a Dual Capacitor to a Single in an Air Conditioner

  1. Anthony McMahon

    I have installed a new condensor fan motor 51-23055-11 and it came with a 3uf fan capacitor. My old motor was a 3 wire and the new is a 5 wire. I installed the motor using the black brown and orange wires and joined the yellow and purple together with a wire nut and everything is up and running. I have not installed the I believe required single run capacitor but wired everything to the dual run capacitor,. Once again everything is running. I want to properly install the single 3uf capacitor and leave the dual run for the compressor side. I believe I should take the brown fan wire from the motor and put it on the 3 uf capacitor but I am not sure if I should take the orange new motor wire off of the dual run capacitor and put it on the 3uf or put a jumper from the dual common to the new 3uf. Please advise ? Your video was somewhat helpful but went to fast when showing your hookup.

  2. Elizabeth A Leac

    Hello, I seem to have a strange setup. I need to replace the contactor and capacitor in my unit. When I opened the box, I found two single capacitors; one round with two prongs and one oval with two prongs. Do I have to continue using two singles or can I go to a round dual capacitor? Thank you.

    1. Don

      A dual round is two capacitors in one package. They can be separate if you do not have a replacement dual round.


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