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Dual Run Capacitor

Dual Run Capacitor Overview

Dual run capacitors are often used in HVAC (heating, ventilation, and air conditioning) units. They are not electrically different from run capacitors that have two terminals, but are convenient to use in HVAC units for reasons listed below.

If you're in need of a replacement one, view our full line of dual run capacitors here.

What is a dual run capacitor?

A dual run capacitor is two run capacitors combined into a single case. It will have three terminals labeled "C," "FAN," and "HERM" for the common, fan, and hermetic compressor connections. A dual run capacitor is often used for air conditioning, heat pump, and ventilation units, which require starting of the condenser fan motor and the compressor.

There are two capacitance ratings in a dual run capacitor, indicated by the format of "45/5 uf," for example. The first, larger rating of 45 uf is between the common and the compressor ("C" and "HERM").The second, smaller rating of 5 uf is between the common and fan ("C" and "FAN").

Common voltage ratings for a dual run capacitor are 370V and 440V. Some dual run capacitors will be rated for both of these voltages. When choosing a replacement dual run capacitor, always make sure that the capacitor’s rating matches or exceeds that of your system voltage. Otherwise, the motor that is installed may become louder, consume more energy, and overheat due to the uneven magnetic field that causes the rotor to slow.

There are two case styles for dual capacitors: oval and round. A round dual run capacitor is interchangeable with an oval one as long as the capacitor fits within the allotted mounting space you have.


How do you know if your dual run capacitor has gone bad? First, do a visual inspection. Is part of the capacitor bulged or swollen? Is it leaking oil? If so, you will need a replacement. If your HVAC unit isn’t turning on, the fan or the compressor doesn’t run, and the breaker on the outdoor unit has been checked and rest, then it is also likely that you need a new dual run capacitor.

View our video below to see how to replace an HVAC capacitor in your air conditioning unit. For a specific tutorial on how to diagnose dual run capacitor problems in your air conditioning unit, check out our Capacitor Troubleshooting Guide.

Product Selection

Click on the part number view detailed specifications, data sheets, and dimensional drawings and to buy a dual capacitor online. Prices for single units include shipping. Free shipping on all lot units!

Round, 370-440 VAC

Capacitance (uf) 1 Piece 5 Lot 10 Lot 25 Lot 50 Lot 100 Lot
35/5 RC0102 » RC0103 » RC0104 » RC0105 » RC0106 » RC0107 »
40/5 RC0108 » RC0109 » RC0110 » RC0111 » RC0112 » RC0113 »
45/5 RC0114 » RC0115 » RC0116 RC0117 » RC0118 » RC0119 »
50/5 RC0120 » RC0121 » RC0122 » RC0123 » RC0124 » RC0125 »
60/5 RC0126 » RC0127 » RC0128 » RC0129 » RC0130 » RC0131 »
70/5 RC0132 » RC0133 » RC0134 » RC0135 » RC0136 » RC0137 »

Capacitor for Motor Help